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ckpts/universal/global_step80/zero/21.mlp.dense_h_to_4h.weight/exp_avg_sq.pt

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+oid sha256:10ffac867fd66942653892d32dbc981ce4da71bbade68a9f9bda032cfeb9d570
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ckpts/universal/global_step80/zero/22.mlp.dense_h_to_4h.weight/exp_avg_sq.pt

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+version https://git-lfs.github.com/spec/v1
+oid sha256:05731306e2fb6b6aec9b81a49efbef979505c9d05179e6b721058725036d1214
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venv/lib/python3.10/site-packages/pandas/tests/indexes/base_class/test_constructors.py

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+import numpy as np
+import pytest
+
+import pandas as pd
+from pandas import (
+    Index,
+    MultiIndex,
+    Series,
+)
+import pandas._testing as tm
+
+
+class TestIndexConstructor:
+    # Tests for the Index constructor, specifically for cases that do
+    #  not return a subclass
+
+    @pytest.mark.parametrize("value", [1, np.int64(1)])
+    def test_constructor_corner(self, value):
+        # corner case
+        msg = (
+            r"Index\(\.\.\.\) must be called with a collection of some "
+            f"kind, {value} was passed"
+        )
+        with pytest.raises(TypeError, match=msg):
+            Index(value)
+
+    @pytest.mark.parametrize("index_vals", [[("A", 1), "B"], ["B", ("A", 1)]])
+    def test_construction_list_mixed_tuples(self, index_vals):
+        # see gh-10697: if we are constructing from a mixed list of tuples,
+        # make sure that we are independent of the sorting order.
+        index = Index(index_vals)
+        assert isinstance(index, Index)
+        assert not isinstance(index, MultiIndex)
+
+    def test_constructor_cast(self):
+        msg = "could not convert string to float"
+        with pytest.raises(ValueError, match=msg):
+            Index(["a", "b", "c"], dtype=float)
+
+    @pytest.mark.parametrize("tuple_list", [[()], [(), ()]])
+    def test_construct_empty_tuples(self, tuple_list):
+        # GH #45608
+        result = Index(tuple_list)
+        expected = MultiIndex.from_tuples(tuple_list)
+
+        tm.assert_index_equal(result, expected)
+
+    def test_index_string_inference(self):
+        # GH#54430
+        pytest.importorskip("pyarrow")
+        dtype = "string[pyarrow_numpy]"
+        expected = Index(["a", "b"], dtype=dtype)
+        with pd.option_context("future.infer_string", True):
+            ser = Index(["a", "b"])
+        tm.assert_index_equal(ser, expected)
+
+        expected = Index(["a", 1], dtype="object")
+        with pd.option_context("future.infer_string", True):
+            ser = Index(["a", 1])
+        tm.assert_index_equal(ser, expected)
+
+    def test_inference_on_pandas_objects(self):
+        # GH#56012
+        idx = Index([pd.Timestamp("2019-12-31")], dtype=object)
+        with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+            result = Index(idx)
+        assert result.dtype != np.object_
+
+        ser = Series([pd.Timestamp("2019-12-31")], dtype=object)
+
+        with tm.assert_produces_warning(FutureWarning, match="Dtype inference"):
+            result = Index(ser)
+        assert result.dtype != np.object_
+
+    def test_constructor_not_read_only(self):
+        # GH#57130
+        ser = Series([1, 2], dtype=object)
+        with pd.option_context("mode.copy_on_write", True):
+            idx = Index(ser)
+            assert idx._values.flags.writeable

venv/lib/python3.10/site-packages/pandas/tests/indexes/base_class/test_formats.py

@@ -0,0 +1,163 @@
+import numpy as np
+import pytest
+
+from pandas._config import using_pyarrow_string_dtype
+import pandas._config.config as cf
+
+from pandas import Index
+import pandas._testing as tm
+
+
+class TestIndexRendering:
+    def test_repr_is_valid_construction_code(self):
+        # for the case of Index, where the repr is traditional rather than
+        # stylized
+        idx = Index(["a", "b"])
+        res = eval(repr(idx))
+        tm.assert_index_equal(res, idx)
+
+    @pytest.mark.xfail(using_pyarrow_string_dtype(), reason="repr different")
+    @pytest.mark.parametrize(
+        "index,expected",
+        [
+            # ASCII
+            # short
+            (
+                Index(["a", "bb", "ccc"]),
+                """Index(['a', 'bb', 'ccc'], dtype='object')""",
+            ),
+            # multiple lines
+            (
+                Index(["a", "bb", "ccc"] * 10),
+                "Index(['a', 'bb', 'ccc', 'a', 'bb', 'ccc', 'a', "
+                "'bb', 'ccc', 'a', 'bb', 'ccc',\n"
+                "       'a', 'bb', 'ccc', 'a', 'bb', 'ccc', 'a', "
+                "'bb', 'ccc', 'a', 'bb', 'ccc',\n"
+                "       'a', 'bb', 'ccc', 'a', 'bb', 'ccc'],\n"
+                "      dtype='object')",
+            ),
+            # truncated
+            (
+                Index(["a", "bb", "ccc"] * 100),
+                "Index(['a', 'bb', 'ccc', 'a', 'bb', 'ccc', 'a', 'bb', 'ccc', 'a',\n"
+                "       ...\n"
+                "       'ccc', 'a', 'bb', 'ccc', 'a', 'bb', 'ccc', 'a', 'bb', 'ccc'],\n"
+                "      dtype='object', length=300)",
+            ),
+            # Non-ASCII
+            # short
+            (
+                Index(["あ", "いい", "ううう"]),
+                """Index(['あ', 'いい', 'ううう'], dtype='object')""",
+            ),
+            # multiple lines
+            (
+                Index(["あ", "いい", "ううう"] * 10),
+                (
+                    "Index(['あ', 'いい', 'ううう', 'あ', 'いい', 'ううう', "
+                    "'あ', 'いい', 'ううう', 'あ', 'いい', 'ううう',\n"
+                    "       'あ', 'いい', 'ううう', 'あ', 'いい', 'ううう', "
+                    "'あ', 'いい', 'ううう', 'あ', 'いい', 'ううう',\n"
+                    "       'あ', 'いい', 'ううう', 'あ', 'いい', "
+                    "'ううう'],\n"
+                    "      dtype='object')"
+                ),
+            ),
+            # truncated
+            (
+                Index(["あ", "いい", "ううう"] * 100),
+                (
+                    "Index(['あ', 'いい', 'ううう', 'あ', 'いい', 'ううう', "
+                    "'あ', 'いい', 'ううう', 'あ',\n"
+                    "       ...\n"
+                    "       'ううう', 'あ', 'いい', 'ううう', 'あ', 'いい', "
+                    "'ううう', 'あ', 'いい', 'ううう'],\n"
+                    "      dtype='object', length=300)"
+                ),
+            ),
+        ],
+    )
+    def test_string_index_repr(self, index, expected):
+        result = repr(index)
+        assert result == expected
+
+    @pytest.mark.xfail(using_pyarrow_string_dtype(), reason="repr different")
+    @pytest.mark.parametrize(
+        "index,expected",
+        [
+            # short
+            (
+                Index(["あ", "いい", "ううう"]),
+                ("Index(['あ', 'いい', 'ううう'], dtype='object')"),
+            ),
+            # multiple lines
+            (
+                Index(["あ", "いい", "ううう"] * 10),
+                (
+                    "Index(['あ', 'いい', 'ううう', 'あ', 'いい', "
+                    "'ううう', 'あ', 'いい', 'ううう',\n"
+                    "       'あ', 'いい', 'ううう', 'あ', 'いい', "
+                    "'ううう', 'あ', 'いい', 'ううう',\n"
+                    "       'あ', 'いい', 'ううう', 'あ', 'いい', "
+                    "'ううう', 'あ', 'いい', 'ううう',\n"
+                    "       'あ', 'いい', 'ううう'],\n"
+                    "      dtype='object')"
+                    ""
+                ),
+            ),
+            # truncated
+            (
+                Index(["あ", "いい", "ううう"] * 100),
+                (
+                    "Index(['あ', 'いい', 'ううう', 'あ', 'いい', "
+                    "'ううう', 'あ', 'いい', 'ううう',\n"
+                    "       'あ',\n"
+                    "       ...\n"
+                    "       'ううう', 'あ', 'いい', 'ううう', 'あ', "
+                    "'いい', 'ううう', 'あ', 'いい',\n"
+                    "       'ううう'],\n"
+                    "      dtype='object', length=300)"
+                ),
+            ),
+        ],
+    )
+    def test_string_index_repr_with_unicode_option(self, index, expected):
+        # Enable Unicode option -----------------------------------------
+        with cf.option_context("display.unicode.east_asian_width", True):
+            result = repr(index)
+            assert result == expected
+
+    def test_repr_summary(self):
+        with cf.option_context("display.max_seq_items", 10):
+            result = repr(Index(np.arange(1000)))
+            assert len(result) < 200
+            assert "..." in result
+
+    def test_summary_bug(self):
+        # GH#3869
+        ind = Index(["{other}%s", "~:{range}:0"], name="A")
+        result = ind._summary()
+        # shouldn't be formatted accidentally.
+        assert "~:{range}:0" in result
+        assert "{other}%s" in result
+
+    def test_index_repr_bool_nan(self):
+        # GH32146
+        arr = Index([True, False, np.nan], dtype=object)
+        msg = "Index.format is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            exp1 = arr.format()
+        out1 = ["True", "False", "NaN"]
+        assert out1 == exp1
+
+        exp2 = repr(arr)
+        out2 = "Index([True, False, nan], dtype='object')"
+        assert out2 == exp2
+
+    def test_format_different_scalar_lengths(self):
+        # GH#35439
+        idx = Index(["aaaaaaaaa", "b"])
+        expected = ["aaaaaaaaa", "b"]
+        msg = r"Index\.format is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            assert idx.format() == expected

venv/lib/python3.10/site-packages/pandas/tests/indexes/base_class/test_indexing.py

@@ -0,0 +1,104 @@
+import numpy as np
+import pytest
+
+from pandas._libs import index as libindex
+
+import pandas as pd
+from pandas import (
+    Index,
+    NaT,
+)
+import pandas._testing as tm
+
+
+class TestGetSliceBounds:
+    @pytest.mark.parametrize("side, expected", [("left", 4), ("right", 5)])
+    def test_get_slice_bounds_within(self, side, expected):
+        index = Index(list("abcdef"))
+        result = index.get_slice_bound("e", side=side)
+        assert result == expected
+
+    @pytest.mark.parametrize("side", ["left", "right"])
+    @pytest.mark.parametrize(
+        "data, bound, expected", [(list("abcdef"), "x", 6), (list("bcdefg"), "a", 0)]
+    )
+    def test_get_slice_bounds_outside(self, side, expected, data, bound):
+        index = Index(data)
+        result = index.get_slice_bound(bound, side=side)
+        assert result == expected
+
+    def test_get_slice_bounds_invalid_side(self):
+        with pytest.raises(ValueError, match="Invalid value for side kwarg"):
+            Index([]).get_slice_bound("a", side="middle")
+
+
+class TestGetIndexerNonUnique:
+    def test_get_indexer_non_unique_dtype_mismatch(self):
+        # GH#25459
+        indexes, missing = Index(["A", "B"]).get_indexer_non_unique(Index([0]))
+        tm.assert_numpy_array_equal(np.array([-1], dtype=np.intp), indexes)
+        tm.assert_numpy_array_equal(np.array([0], dtype=np.intp), missing)
+
+    @pytest.mark.parametrize(
+        "idx_values,idx_non_unique",
+        [
+            ([np.nan, 100, 200, 100], [np.nan, 100]),
+            ([np.nan, 100.0, 200.0, 100.0], [np.nan, 100.0]),
+        ],
+    )
+    def test_get_indexer_non_unique_int_index(self, idx_values, idx_non_unique):
+        indexes, missing = Index(idx_values).get_indexer_non_unique(Index([np.nan]))
+        tm.assert_numpy_array_equal(np.array([0], dtype=np.intp), indexes)
+        tm.assert_numpy_array_equal(np.array([], dtype=np.intp), missing)
+
+        indexes, missing = Index(idx_values).get_indexer_non_unique(
+            Index(idx_non_unique)
+        )
+        tm.assert_numpy_array_equal(np.array([0, 1, 3], dtype=np.intp), indexes)
+        tm.assert_numpy_array_equal(np.array([], dtype=np.intp), missing)
+
+
+class TestGetLoc:
+    @pytest.mark.slow  # to_flat_index takes a while
+    def test_get_loc_tuple_monotonic_above_size_cutoff(self, monkeypatch):
+        # Go through the libindex path for which using
+        # _bin_search vs ndarray.searchsorted makes a difference
+
+        with monkeypatch.context():
+            monkeypatch.setattr(libindex, "_SIZE_CUTOFF", 100)
+            lev = list("ABCD")
+            dti = pd.date_range("2016-01-01", periods=10)
+
+            mi = pd.MultiIndex.from_product([lev, range(5), dti])
+            oidx = mi.to_flat_index()
+
+            loc = len(oidx) // 2
+            tup = oidx[loc]
+
+            res = oidx.get_loc(tup)
+        assert res == loc
+
+    def test_get_loc_nan_object_dtype_nonmonotonic_nonunique(self):
+        # case that goes through _maybe_get_bool_indexer
+        idx = Index(["foo", np.nan, None, "foo", 1.0, None], dtype=object)
+
+        # we dont raise KeyError on nan
+        res = idx.get_loc(np.nan)
+        assert res == 1
+
+        # we only match on None, not on np.nan
+        res = idx.get_loc(None)
+        expected = np.array([False, False, True, False, False, True])
+        tm.assert_numpy_array_equal(res, expected)
+
+        # we don't match at all on mismatched NA
+        with pytest.raises(KeyError, match="NaT"):
+            idx.get_loc(NaT)
+
+
+def test_getitem_boolean_ea_indexer():
+    # GH#45806
+    ser = pd.Series([True, False, pd.NA], dtype="boolean")
+    result = ser.index[ser]
+    expected = Index([0])
+    tm.assert_index_equal(result, expected)

venv/lib/python3.10/site-packages/pandas/tests/indexes/base_class/test_pickle.py

@@ -0,0 +1,11 @@
+from pandas import Index
+import pandas._testing as tm
+
+
+def test_pickle_preserves_object_dtype():
+    # GH#43188, GH#43155 don't infer numeric dtype
+    index = Index([1, 2, 3], dtype=object)
+
+    result = tm.round_trip_pickle(index)
+    assert result.dtype == object
+    tm.assert_index_equal(index, result)

venv/lib/python3.10/site-packages/pandas/tests/indexes/base_class/test_reshape.py

@@ -0,0 +1,95 @@
+"""
+Tests for ndarray-like method on the base Index class
+"""
+import numpy as np
+import pytest
+
+from pandas import Index
+import pandas._testing as tm
+
+
+class TestReshape:
+    def test_repeat(self):
+        repeats = 2
+        index = Index([1, 2, 3])
+        expected = Index([1, 1, 2, 2, 3, 3])
+
+        result = index.repeat(repeats)
+        tm.assert_index_equal(result, expected)
+
+    def test_insert(self):
+        # GH 7256
+        # validate neg/pos inserts
+        result = Index(["b", "c", "d"])
+
+        # test 0th element
+        tm.assert_index_equal(Index(["a", "b", "c", "d"]), result.insert(0, "a"))
+
+        # test Nth element that follows Python list behavior
+        tm.assert_index_equal(Index(["b", "c", "e", "d"]), result.insert(-1, "e"))
+
+        # test loc +/- neq (0, -1)
+        tm.assert_index_equal(result.insert(1, "z"), result.insert(-2, "z"))
+
+        # test empty
+        null_index = Index([])
+        tm.assert_index_equal(Index(["a"], dtype=object), null_index.insert(0, "a"))
+
+    def test_insert_missing(self, nulls_fixture, using_infer_string):
+        # GH#22295
+        # test there is no mangling of NA values
+        expected = Index(["a", nulls_fixture, "b", "c"], dtype=object)
+        result = Index(list("abc"), dtype=object).insert(
+            1, Index([nulls_fixture], dtype=object)
+        )
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "val", [(1, 2), np.datetime64("2019-12-31"), np.timedelta64(1, "D")]
+    )
+    @pytest.mark.parametrize("loc", [-1, 2])
+    def test_insert_datetime_into_object(self, loc, val):
+        # GH#44509
+        idx = Index(["1", "2", "3"])
+        result = idx.insert(loc, val)
+        expected = Index(["1", "2", val, "3"])
+        tm.assert_index_equal(result, expected)
+        assert type(expected[2]) is type(val)
+
+    def test_insert_none_into_string_numpy(self):
+        # GH#55365
+        pytest.importorskip("pyarrow")
+        index = Index(["a", "b", "c"], dtype="string[pyarrow_numpy]")
+        result = index.insert(-1, None)
+        expected = Index(["a", "b", None, "c"], dtype="string[pyarrow_numpy]")
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "pos,expected",
+        [
+            (0, Index(["b", "c", "d"], name="index")),
+            (-1, Index(["a", "b", "c"], name="index")),
+        ],
+    )
+    def test_delete(self, pos, expected):
+        index = Index(["a", "b", "c", "d"], name="index")
+        result = index.delete(pos)
+        tm.assert_index_equal(result, expected)
+        assert result.name == expected.name
+
+    def test_delete_raises(self):
+        index = Index(["a", "b", "c", "d"], name="index")
+        msg = "index 5 is out of bounds for axis 0 with size 4"
+        with pytest.raises(IndexError, match=msg):
+            index.delete(5)
+
+    def test_append_multiple(self):
+        index = Index(["a", "b", "c", "d", "e", "f"])
+
+        foos = [index[:2], index[2:4], index[4:]]
+        result = foos[0].append(foos[1:])
+        tm.assert_index_equal(result, index)
+
+        # empty
+        result = index.append([])
+        tm.assert_index_equal(result, index)

venv/lib/python3.10/site-packages/pandas/tests/indexes/base_class/test_setops.py

@@ -0,0 +1,266 @@
+from datetime import datetime
+
+import numpy as np
+import pytest
+
+import pandas as pd
+from pandas import (
+    Index,
+    Series,
+)
+import pandas._testing as tm
+from pandas.core.algorithms import safe_sort
+
+
+def equal_contents(arr1, arr2) -> bool:
+    """
+    Checks if the set of unique elements of arr1 and arr2 are equivalent.
+    """
+    return frozenset(arr1) == frozenset(arr2)
+
+
+class TestIndexSetOps:
+    @pytest.mark.parametrize(
+        "method", ["union", "intersection", "difference", "symmetric_difference"]
+    )
+    def test_setops_sort_validation(self, method):
+        idx1 = Index(["a", "b"])
+        idx2 = Index(["b", "c"])
+
+        with pytest.raises(ValueError, match="The 'sort' keyword only takes"):
+            getattr(idx1, method)(idx2, sort=2)
+
+        # sort=True is supported as of GH#??
+        getattr(idx1, method)(idx2, sort=True)
+
+    def test_setops_preserve_object_dtype(self):
+        idx = Index([1, 2, 3], dtype=object)
+        result = idx.intersection(idx[1:])
+        expected = idx[1:]
+        tm.assert_index_equal(result, expected)
+
+        # if other is not monotonic increasing, intersection goes through
+        #  a different route
+        result = idx.intersection(idx[1:][::-1])
+        tm.assert_index_equal(result, expected)
+
+        result = idx._union(idx[1:], sort=None)
+        expected = idx
+        tm.assert_numpy_array_equal(result, expected.values)
+
+        result = idx.union(idx[1:], sort=None)
+        tm.assert_index_equal(result, expected)
+
+        # if other is not monotonic increasing, _union goes through
+        #  a different route
+        result = idx._union(idx[1:][::-1], sort=None)
+        tm.assert_numpy_array_equal(result, expected.values)
+
+        result = idx.union(idx[1:][::-1], sort=None)
+        tm.assert_index_equal(result, expected)
+
+    def test_union_base(self):
+        index = Index([0, "a", 1, "b", 2, "c"])
+        first = index[3:]
+        second = index[:5]
+
+        result = first.union(second)
+
+        expected = Index([0, 1, 2, "a", "b", "c"])
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize("klass", [np.array, Series, list])
+    def test_union_different_type_base(self, klass):
+        # GH 10149
+        index = Index([0, "a", 1, "b", 2, "c"])
+        first = index[3:]
+        second = index[:5]
+
+        result = first.union(klass(second.values))
+
+        assert equal_contents(result, index)
+
+    def test_union_sort_other_incomparable(self):
+        # https://github.com/pandas-dev/pandas/issues/24959
+        idx = Index([1, pd.Timestamp("2000")])
+        # default (sort=None)
+        with tm.assert_produces_warning(RuntimeWarning):
+            result = idx.union(idx[:1])
+
+        tm.assert_index_equal(result, idx)
+
+        # sort=None
+        with tm.assert_produces_warning(RuntimeWarning):
+            result = idx.union(idx[:1], sort=None)
+        tm.assert_index_equal(result, idx)
+
+        # sort=False
+        result = idx.union(idx[:1], sort=False)
+        tm.assert_index_equal(result, idx)
+
+    def test_union_sort_other_incomparable_true(self):
+        idx = Index([1, pd.Timestamp("2000")])
+        with pytest.raises(TypeError, match=".*"):
+            idx.union(idx[:1], sort=True)
+
+    def test_intersection_equal_sort_true(self):
+        idx = Index(["c", "a", "b"])
+        sorted_ = Index(["a", "b", "c"])
+        tm.assert_index_equal(idx.intersection(idx, sort=True), sorted_)
+
+    def test_intersection_base(self, sort):
+        # (same results for py2 and py3 but sortedness not tested elsewhere)
+        index = Index([0, "a", 1, "b", 2, "c"])
+        first = index[:5]
+        second = index[:3]
+
+        expected = Index([0, 1, "a"]) if sort is None else Index([0, "a", 1])
+        result = first.intersection(second, sort=sort)
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize("klass", [np.array, Series, list])
+    def test_intersection_different_type_base(self, klass, sort):
+        # GH 10149
+        index = Index([0, "a", 1, "b", 2, "c"])
+        first = index[:5]
+        second = index[:3]
+
+        result = first.intersection(klass(second.values), sort=sort)
+        assert equal_contents(result, second)
+
+    def test_intersection_nosort(self):
+        result = Index(["c", "b", "a"]).intersection(["b", "a"])
+        expected = Index(["b", "a"])
+        tm.assert_index_equal(result, expected)
+
+    def test_intersection_equal_sort(self):
+        idx = Index(["c", "a", "b"])
+        tm.assert_index_equal(idx.intersection(idx, sort=False), idx)
+        tm.assert_index_equal(idx.intersection(idx, sort=None), idx)
+
+    def test_intersection_str_dates(self, sort):
+        dt_dates = [datetime(2012, 2, 9), datetime(2012, 2, 22)]
+
+        i1 = Index(dt_dates, dtype=object)
+        i2 = Index(["aa"], dtype=object)
+        result = i2.intersection(i1, sort=sort)
+
+        assert len(result) == 0
+
+    @pytest.mark.parametrize(
+        "index2,expected_arr",
+        [(Index(["B", "D"]), ["B"]), (Index(["B", "D", "A"]), ["A", "B"])],
+    )
+    def test_intersection_non_monotonic_non_unique(self, index2, expected_arr, sort):
+        # non-monotonic non-unique
+        index1 = Index(["A", "B", "A", "C"])
+        expected = Index(expected_arr)
+        result = index1.intersection(index2, sort=sort)
+        if sort is None:
+            expected = expected.sort_values()
+        tm.assert_index_equal(result, expected)
+
+    def test_difference_base(self, sort):
+        # (same results for py2 and py3 but sortedness not tested elsewhere)
+        index = Index([0, "a", 1, "b", 2, "c"])
+        first = index[:4]
+        second = index[3:]
+
+        result = first.difference(second, sort)
+        expected = Index([0, "a", 1])
+        if sort is None:
+            expected = Index(safe_sort(expected))
+        tm.assert_index_equal(result, expected)
+
+    def test_symmetric_difference(self):
+        # (same results for py2 and py3 but sortedness not tested elsewhere)
+        index = Index([0, "a", 1, "b", 2, "c"])
+        first = index[:4]
+        second = index[3:]
+
+        result = first.symmetric_difference(second)
+        expected = Index([0, 1, 2, "a", "c"])
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "method,expected,sort",
+        [
+            (
+                "intersection",
+                np.array(
+                    [(1, "A"), (2, "A"), (1, "B"), (2, "B")],
+                    dtype=[("num", int), ("let", "S1")],
+                ),
+                False,
+            ),
+            (
+                "intersection",
+                np.array(
+                    [(1, "A"), (1, "B"), (2, "A"), (2, "B")],
+                    dtype=[("num", int), ("let", "S1")],
+                ),
+                None,
+            ),
+            (
+                "union",
+                np.array(
+                    [(1, "A"), (1, "B"), (1, "C"), (2, "A"), (2, "B"), (2, "C")],
+                    dtype=[("num", int), ("let", "S1")],
+                ),
+                None,
+            ),
+        ],
+    )
+    def test_tuple_union_bug(self, method, expected, sort):
+        index1 = Index(
+            np.array(
+                [(1, "A"), (2, "A"), (1, "B"), (2, "B")],
+                dtype=[("num", int), ("let", "S1")],
+            )
+        )
+        index2 = Index(
+            np.array(
+                [(1, "A"), (2, "A"), (1, "B"), (2, "B"), (1, "C"), (2, "C")],
+                dtype=[("num", int), ("let", "S1")],
+            )
+        )
+
+        result = getattr(index1, method)(index2, sort=sort)
+        assert result.ndim == 1
+
+        expected = Index(expected)
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize("first_list", [["b", "a"], []])
+    @pytest.mark.parametrize("second_list", [["a", "b"], []])
+    @pytest.mark.parametrize(
+        "first_name, second_name, expected_name",
+        [("A", "B", None), (None, "B", None), ("A", None, None)],
+    )
+    def test_union_name_preservation(
+        self, first_list, second_list, first_name, second_name, expected_name, sort
+    ):
+        first = Index(first_list, name=first_name)
+        second = Index(second_list, name=second_name)
+        union = first.union(second, sort=sort)
+
+        vals = set(first_list).union(second_list)
+
+        if sort is None and len(first_list) > 0 and len(second_list) > 0:
+            expected = Index(sorted(vals), name=expected_name)
+            tm.assert_index_equal(union, expected)
+        else:
+            expected = Index(vals, name=expected_name)
+            tm.assert_index_equal(union.sort_values(), expected.sort_values())
+
+    @pytest.mark.parametrize(
+        "diff_type, expected",
+        [["difference", [1, "B"]], ["symmetric_difference", [1, 2, "B", "C"]]],
+    )
+    def test_difference_object_type(self, diff_type, expected):
+        # GH 13432
+        idx1 = Index([0, 1, "A", "B"])
+        idx2 = Index([0, 2, "A", "C"])
+        result = getattr(idx1, diff_type)(idx2)
+        expected = Index(expected)
+        tm.assert_index_equal(result, expected)

venv/lib/python3.10/site-packages/pandas/tests/indexes/base_class/test_where.py

@@ -0,0 +1,13 @@
+import numpy as np
+
+from pandas import Index
+import pandas._testing as tm
+
+
+class TestWhere:
+    def test_where_intlike_str_doesnt_cast_ints(self):
+        idx = Index(range(3))
+        mask = np.array([True, False, True])
+        res = idx.where(mask, "2")
+        expected = Index([0, "2", 2])
+        tm.assert_index_equal(res, expected)

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_arithmetic.py

@@ -0,0 +1,56 @@
+# Arithmetic tests specific to DatetimeIndex are generally about `freq`
+#  rentention or inference.  Other arithmetic tests belong in
+#  tests/arithmetic/test_datetime64.py
+import pytest
+
+from pandas import (
+    Timedelta,
+    TimedeltaIndex,
+    Timestamp,
+    date_range,
+    timedelta_range,
+)
+import pandas._testing as tm
+
+
+class TestDatetimeIndexArithmetic:
+    def test_add_timedelta_preserves_freq(self):
+        # GH#37295 should hold for any DTI with freq=None or Tick freq
+        tz = "Canada/Eastern"
+        dti = date_range(
+            start=Timestamp("2019-03-26 00:00:00-0400", tz=tz),
+            end=Timestamp("2020-10-17 00:00:00-0400", tz=tz),
+            freq="D",
+        )
+        result = dti + Timedelta(days=1)
+        assert result.freq == dti.freq
+
+    def test_sub_datetime_preserves_freq(self, tz_naive_fixture):
+        # GH#48818
+        dti = date_range("2016-01-01", periods=12, tz=tz_naive_fixture)
+
+        res = dti - dti[0]
+        expected = timedelta_range("0 Days", "11 Days")
+        tm.assert_index_equal(res, expected)
+        assert res.freq == expected.freq
+
+    @pytest.mark.xfail(
+        reason="The inherited freq is incorrect bc dti.freq is incorrect "
+        "https://github.com/pandas-dev/pandas/pull/48818/files#r982793461"
+    )
+    def test_sub_datetime_preserves_freq_across_dst(self):
+        # GH#48818
+        ts = Timestamp("2016-03-11", tz="US/Pacific")
+        dti = date_range(ts, periods=4)
+
+        res = dti - dti[0]
+        expected = TimedeltaIndex(
+            [
+                Timedelta(days=0),
+                Timedelta(days=1),
+                Timedelta(days=2),
+                Timedelta(days=2, hours=23),
+            ]
+        )
+        tm.assert_index_equal(res, expected)
+        assert res.freq == expected.freq

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_constructors.py

@@ -0,0 +1,1204 @@
+from __future__ import annotations
+
+from datetime import (
+    datetime,
+    timedelta,
+    timezone,
+)
+from functools import partial
+from operator import attrgetter
+
+import dateutil
+import dateutil.tz
+from dateutil.tz import gettz
+import numpy as np
+import pytest
+import pytz
+
+from pandas._libs.tslibs import (
+    OutOfBoundsDatetime,
+    astype_overflowsafe,
+    timezones,
+)
+
+import pandas as pd
+from pandas import (
+    DatetimeIndex,
+    Index,
+    Timestamp,
+    date_range,
+    offsets,
+    to_datetime,
+)
+import pandas._testing as tm
+from pandas.core.arrays import period_array
+
+
+class TestDatetimeIndex:
+    def test_closed_deprecated(self):
+        # GH#52628
+        msg = "The 'closed' keyword"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            DatetimeIndex([], closed=True)
+
+    def test_normalize_deprecated(self):
+        # GH#52628
+        msg = "The 'normalize' keyword"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            DatetimeIndex([], normalize=True)
+
+    def test_from_dt64_unsupported_unit(self):
+        # GH#49292
+        val = np.datetime64(1, "D")
+        result = DatetimeIndex([val], tz="US/Pacific")
+
+        expected = DatetimeIndex([val.astype("M8[s]")], tz="US/Pacific")
+        tm.assert_index_equal(result, expected)
+
+    def test_explicit_tz_none(self):
+        # GH#48659
+        dti = date_range("2016-01-01", periods=10, tz="UTC")
+
+        msg = "Passed data is timezone-aware, incompatible with 'tz=None'"
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex(dti, tz=None)
+
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex(np.array(dti), tz=None)
+
+        msg = "Cannot pass both a timezone-aware dtype and tz=None"
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex([], dtype="M8[ns, UTC]", tz=None)
+
+    def test_freq_validation_with_nat(self):
+        # GH#11587 make sure we get a useful error message when generate_range
+        #  raises
+        msg = (
+            "Inferred frequency None from passed values does not conform "
+            "to passed frequency D"
+        )
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex([pd.NaT, Timestamp("2011-01-01")], freq="D")
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex([pd.NaT, Timestamp("2011-01-01")._value], freq="D")
+
+    # TODO: better place for tests shared by DTI/TDI?
+    @pytest.mark.parametrize(
+        "index",
+        [
+            date_range("2016-01-01", periods=5, tz="US/Pacific"),
+            pd.timedelta_range("1 Day", periods=5),
+        ],
+    )
+    def test_shallow_copy_inherits_array_freq(self, index):
+        # If we pass a DTA/TDA to shallow_copy and dont specify a freq,
+        #  we should inherit the array's freq, not our own.
+        array = index._data
+
+        arr = array[[0, 3, 2, 4, 1]]
+        assert arr.freq is None
+
+        result = index._shallow_copy(arr)
+        assert result.freq is None
+
+    def test_categorical_preserves_tz(self):
+        # GH#18664 retain tz when going DTI-->Categorical-->DTI
+        dti = DatetimeIndex(
+            [pd.NaT, "2015-01-01", "1999-04-06 15:14:13", "2015-01-01"], tz="US/Eastern"
+        )
+
+        for dtobj in [dti, dti._data]:
+            # works for DatetimeIndex or DatetimeArray
+
+            ci = pd.CategoricalIndex(dtobj)
+            carr = pd.Categorical(dtobj)
+            cser = pd.Series(ci)
+
+            for obj in [ci, carr, cser]:
+                result = DatetimeIndex(obj)
+                tm.assert_index_equal(result, dti)
+
+    def test_dti_with_period_data_raises(self):
+        # GH#23675
+        data = pd.PeriodIndex(["2016Q1", "2016Q2"], freq="Q")
+
+        with pytest.raises(TypeError, match="PeriodDtype data is invalid"):
+            DatetimeIndex(data)
+
+        with pytest.raises(TypeError, match="PeriodDtype data is invalid"):
+            to_datetime(data)
+
+        with pytest.raises(TypeError, match="PeriodDtype data is invalid"):
+            DatetimeIndex(period_array(data))
+
+        with pytest.raises(TypeError, match="PeriodDtype data is invalid"):
+            to_datetime(period_array(data))
+
+    def test_dti_with_timedelta64_data_raises(self):
+        # GH#23675 deprecated, enforrced in GH#29794
+        data = np.array([0], dtype="m8[ns]")
+        msg = r"timedelta64\[ns\] cannot be converted to datetime64"
+        with pytest.raises(TypeError, match=msg):
+            DatetimeIndex(data)
+
+        with pytest.raises(TypeError, match=msg):
+            to_datetime(data)
+
+        with pytest.raises(TypeError, match=msg):
+            DatetimeIndex(pd.TimedeltaIndex(data))
+
+        with pytest.raises(TypeError, match=msg):
+            to_datetime(pd.TimedeltaIndex(data))
+
+    def test_constructor_from_sparse_array(self):
+        # https://github.com/pandas-dev/pandas/issues/35843
+        values = [
+            Timestamp("2012-05-01T01:00:00.000000"),
+            Timestamp("2016-05-01T01:00:00.000000"),
+        ]
+        arr = pd.arrays.SparseArray(values)
+        result = Index(arr)
+        assert type(result) is Index
+        assert result.dtype == arr.dtype
+
+    def test_construction_caching(self):
+        df = pd.DataFrame(
+            {
+                "dt": date_range("20130101", periods=3),
+                "dttz": date_range("20130101", periods=3, tz="US/Eastern"),
+                "dt_with_null": [
+                    Timestamp("20130101"),
+                    pd.NaT,
+                    Timestamp("20130103"),
+                ],
+                "dtns": date_range("20130101", periods=3, freq="ns"),
+            }
+        )
+        assert df.dttz.dtype.tz.zone == "US/Eastern"
+
+    @pytest.mark.parametrize(
+        "kwargs",
+        [{"tz": "dtype.tz"}, {"dtype": "dtype"}, {"dtype": "dtype", "tz": "dtype.tz"}],
+    )
+    def test_construction_with_alt(self, kwargs, tz_aware_fixture):
+        tz = tz_aware_fixture
+        i = date_range("20130101", periods=5, freq="h", tz=tz)
+        kwargs = {key: attrgetter(val)(i) for key, val in kwargs.items()}
+        result = DatetimeIndex(i, **kwargs)
+        tm.assert_index_equal(i, result)
+
+    @pytest.mark.parametrize(
+        "kwargs",
+        [{"tz": "dtype.tz"}, {"dtype": "dtype"}, {"dtype": "dtype", "tz": "dtype.tz"}],
+    )
+    def test_construction_with_alt_tz_localize(self, kwargs, tz_aware_fixture):
+        tz = tz_aware_fixture
+        i = date_range("20130101", periods=5, freq="h", tz=tz)
+        i = i._with_freq(None)
+        kwargs = {key: attrgetter(val)(i) for key, val in kwargs.items()}
+
+        if "tz" in kwargs:
+            result = DatetimeIndex(i.asi8, tz="UTC").tz_convert(kwargs["tz"])
+
+            expected = DatetimeIndex(i, **kwargs)
+            tm.assert_index_equal(result, expected)
+
+        # localize into the provided tz
+        i2 = DatetimeIndex(i.tz_localize(None).asi8, tz="UTC")
+        expected = i.tz_localize(None).tz_localize("UTC")
+        tm.assert_index_equal(i2, expected)
+
+        # incompat tz/dtype
+        msg = "cannot supply both a tz and a dtype with a tz"
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex(i.tz_localize(None).asi8, dtype=i.dtype, tz="US/Pacific")
+
+    def test_construction_index_with_mixed_timezones(self):
+        # gh-11488: no tz results in DatetimeIndex
+        result = Index([Timestamp("2011-01-01"), Timestamp("2011-01-02")], name="idx")
+        exp = DatetimeIndex(
+            [Timestamp("2011-01-01"), Timestamp("2011-01-02")], name="idx"
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+        assert result.tz is None
+
+        # same tz results in DatetimeIndex
+        result = Index(
+            [
+                Timestamp("2011-01-01 10:00", tz="Asia/Tokyo"),
+                Timestamp("2011-01-02 10:00", tz="Asia/Tokyo"),
+            ],
+            name="idx",
+        )
+        exp = DatetimeIndex(
+            [Timestamp("2011-01-01 10:00"), Timestamp("2011-01-02 10:00")],
+            tz="Asia/Tokyo",
+            name="idx",
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+        assert result.tz is not None
+        assert result.tz == exp.tz
+
+        # same tz results in DatetimeIndex (DST)
+        result = Index(
+            [
+                Timestamp("2011-01-01 10:00", tz="US/Eastern"),
+                Timestamp("2011-08-01 10:00", tz="US/Eastern"),
+            ],
+            name="idx",
+        )
+        exp = DatetimeIndex(
+            [Timestamp("2011-01-01 10:00"), Timestamp("2011-08-01 10:00")],
+            tz="US/Eastern",
+            name="idx",
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+        assert result.tz is not None
+        assert result.tz == exp.tz
+
+        # Different tz results in Index(dtype=object)
+        result = Index(
+            [
+                Timestamp("2011-01-01 10:00"),
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            name="idx",
+        )
+        exp = Index(
+            [
+                Timestamp("2011-01-01 10:00"),
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            dtype="object",
+            name="idx",
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert not isinstance(result, DatetimeIndex)
+
+        result = Index(
+            [
+                Timestamp("2011-01-01 10:00", tz="Asia/Tokyo"),
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            name="idx",
+        )
+        exp = Index(
+            [
+                Timestamp("2011-01-01 10:00", tz="Asia/Tokyo"),
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            dtype="object",
+            name="idx",
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert not isinstance(result, DatetimeIndex)
+
+        msg = "DatetimeIndex has mixed timezones"
+        msg_depr = "parsing datetimes with mixed time zones will raise an error"
+        with pytest.raises(TypeError, match=msg):
+            with tm.assert_produces_warning(FutureWarning, match=msg_depr):
+                DatetimeIndex(["2013-11-02 22:00-05:00", "2013-11-03 22:00-06:00"])
+
+        # length = 1
+        result = Index([Timestamp("2011-01-01")], name="idx")
+        exp = DatetimeIndex([Timestamp("2011-01-01")], name="idx")
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+        assert result.tz is None
+
+        # length = 1 with tz
+        result = Index([Timestamp("2011-01-01 10:00", tz="Asia/Tokyo")], name="idx")
+        exp = DatetimeIndex(
+            [Timestamp("2011-01-01 10:00")], tz="Asia/Tokyo", name="idx"
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+        assert result.tz is not None
+        assert result.tz == exp.tz
+
+    def test_construction_index_with_mixed_timezones_with_NaT(self):
+        # see gh-11488
+        result = Index(
+            [pd.NaT, Timestamp("2011-01-01"), pd.NaT, Timestamp("2011-01-02")],
+            name="idx",
+        )
+        exp = DatetimeIndex(
+            [pd.NaT, Timestamp("2011-01-01"), pd.NaT, Timestamp("2011-01-02")],
+            name="idx",
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+        assert result.tz is None
+
+        # Same tz results in DatetimeIndex
+        result = Index(
+            [
+                pd.NaT,
+                Timestamp("2011-01-01 10:00", tz="Asia/Tokyo"),
+                pd.NaT,
+                Timestamp("2011-01-02 10:00", tz="Asia/Tokyo"),
+            ],
+            name="idx",
+        )
+        exp = DatetimeIndex(
+            [
+                pd.NaT,
+                Timestamp("2011-01-01 10:00"),
+                pd.NaT,
+                Timestamp("2011-01-02 10:00"),
+            ],
+            tz="Asia/Tokyo",
+            name="idx",
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+        assert result.tz is not None
+        assert result.tz == exp.tz
+
+        # same tz results in DatetimeIndex (DST)
+        result = Index(
+            [
+                Timestamp("2011-01-01 10:00", tz="US/Eastern"),
+                pd.NaT,
+                Timestamp("2011-08-01 10:00", tz="US/Eastern"),
+            ],
+            name="idx",
+        )
+        exp = DatetimeIndex(
+            [Timestamp("2011-01-01 10:00"), pd.NaT, Timestamp("2011-08-01 10:00")],
+            tz="US/Eastern",
+            name="idx",
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+        assert result.tz is not None
+        assert result.tz == exp.tz
+
+        # different tz results in Index(dtype=object)
+        result = Index(
+            [
+                pd.NaT,
+                Timestamp("2011-01-01 10:00"),
+                pd.NaT,
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            name="idx",
+        )
+        exp = Index(
+            [
+                pd.NaT,
+                Timestamp("2011-01-01 10:00"),
+                pd.NaT,
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            dtype="object",
+            name="idx",
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert not isinstance(result, DatetimeIndex)
+
+        result = Index(
+            [
+                pd.NaT,
+                Timestamp("2011-01-01 10:00", tz="Asia/Tokyo"),
+                pd.NaT,
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            name="idx",
+        )
+        exp = Index(
+            [
+                pd.NaT,
+                Timestamp("2011-01-01 10:00", tz="Asia/Tokyo"),
+                pd.NaT,
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            dtype="object",
+            name="idx",
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert not isinstance(result, DatetimeIndex)
+
+        # all NaT
+        result = Index([pd.NaT, pd.NaT], name="idx")
+        exp = DatetimeIndex([pd.NaT, pd.NaT], name="idx")
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+        assert result.tz is None
+
+    def test_construction_dti_with_mixed_timezones(self):
+        # GH 11488 (not changed, added explicit tests)
+
+        # no tz results in DatetimeIndex
+        result = DatetimeIndex(
+            [Timestamp("2011-01-01"), Timestamp("2011-01-02")], name="idx"
+        )
+        exp = DatetimeIndex(
+            [Timestamp("2011-01-01"), Timestamp("2011-01-02")], name="idx"
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+
+        # same tz results in DatetimeIndex
+        result = DatetimeIndex(
+            [
+                Timestamp("2011-01-01 10:00", tz="Asia/Tokyo"),
+                Timestamp("2011-01-02 10:00", tz="Asia/Tokyo"),
+            ],
+            name="idx",
+        )
+        exp = DatetimeIndex(
+            [Timestamp("2011-01-01 10:00"), Timestamp("2011-01-02 10:00")],
+            tz="Asia/Tokyo",
+            name="idx",
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+
+        # same tz results in DatetimeIndex (DST)
+        result = DatetimeIndex(
+            [
+                Timestamp("2011-01-01 10:00", tz="US/Eastern"),
+                Timestamp("2011-08-01 10:00", tz="US/Eastern"),
+            ],
+            name="idx",
+        )
+        exp = DatetimeIndex(
+            [Timestamp("2011-01-01 10:00"), Timestamp("2011-08-01 10:00")],
+            tz="US/Eastern",
+            name="idx",
+        )
+        tm.assert_index_equal(result, exp, exact=True)
+        assert isinstance(result, DatetimeIndex)
+
+        # tz mismatch affecting to tz-aware raises TypeError/ValueError
+
+        msg = "cannot be converted to datetime64"
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex(
+                [
+                    Timestamp("2011-01-01 10:00", tz="Asia/Tokyo"),
+                    Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+                ],
+                name="idx",
+            )
+
+        # pre-2.0 this raised bc of awareness mismatch. in 2.0 with a tz#
+        #  specified we behave as if this was called pointwise, so
+        #  the naive Timestamp is treated as a wall time.
+        dti = DatetimeIndex(
+            [
+                Timestamp("2011-01-01 10:00"),
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            tz="Asia/Tokyo",
+            name="idx",
+        )
+        expected = DatetimeIndex(
+            [
+                Timestamp("2011-01-01 10:00", tz="Asia/Tokyo"),
+                Timestamp("2011-01-02 10:00", tz="US/Eastern").tz_convert("Asia/Tokyo"),
+            ],
+            tz="Asia/Tokyo",
+            name="idx",
+        )
+        tm.assert_index_equal(dti, expected)
+
+        # pre-2.0 mixed-tz scalars raised even if a tz/dtype was specified.
+        #  as of 2.0 we successfully return the requested tz/dtype
+        dti = DatetimeIndex(
+            [
+                Timestamp("2011-01-01 10:00", tz="Asia/Tokyo"),
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            tz="US/Eastern",
+            name="idx",
+        )
+        expected = DatetimeIndex(
+            [
+                Timestamp("2011-01-01 10:00", tz="Asia/Tokyo").tz_convert("US/Eastern"),
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            tz="US/Eastern",
+            name="idx",
+        )
+        tm.assert_index_equal(dti, expected)
+
+        # same thing but pass dtype instead of tz
+        dti = DatetimeIndex(
+            [
+                Timestamp("2011-01-01 10:00", tz="Asia/Tokyo"),
+                Timestamp("2011-01-02 10:00", tz="US/Eastern"),
+            ],
+            dtype="M8[ns, US/Eastern]",
+            name="idx",
+        )
+        tm.assert_index_equal(dti, expected)
+
+    def test_construction_base_constructor(self):
+        arr = [Timestamp("2011-01-01"), pd.NaT, Timestamp("2011-01-03")]
+        tm.assert_index_equal(Index(arr), DatetimeIndex(arr))
+        tm.assert_index_equal(Index(np.array(arr)), DatetimeIndex(np.array(arr)))
+
+        arr = [np.nan, pd.NaT, Timestamp("2011-01-03")]
+        tm.assert_index_equal(Index(arr), DatetimeIndex(arr))
+        tm.assert_index_equal(Index(np.array(arr)), DatetimeIndex(np.array(arr)))
+
+    def test_construction_outofbounds(self):
+        # GH 13663
+        dates = [
+            datetime(3000, 1, 1),
+            datetime(4000, 1, 1),
+            datetime(5000, 1, 1),
+            datetime(6000, 1, 1),
+        ]
+        exp = Index(dates, dtype=object)
+        # coerces to object
+        tm.assert_index_equal(Index(dates), exp)
+
+        msg = "^Out of bounds nanosecond timestamp: 3000-01-01 00:00:00, at position 0$"
+        with pytest.raises(OutOfBoundsDatetime, match=msg):
+            # can't create DatetimeIndex
+            DatetimeIndex(dates)
+
+    @pytest.mark.parametrize("data", [["1400-01-01"], [datetime(1400, 1, 1)]])
+    def test_dti_date_out_of_range(self, data):
+        # GH#1475
+        msg = (
+            "^Out of bounds nanosecond timestamp: "
+            "1400-01-01( 00:00:00)?, at position 0$"
+        )
+        with pytest.raises(OutOfBoundsDatetime, match=msg):
+            DatetimeIndex(data)
+
+    def test_construction_with_ndarray(self):
+        # GH 5152
+        dates = [datetime(2013, 10, 7), datetime(2013, 10, 8), datetime(2013, 10, 9)]
+        data = DatetimeIndex(dates, freq=offsets.BDay()).values
+        result = DatetimeIndex(data, freq=offsets.BDay())
+        expected = DatetimeIndex(["2013-10-07", "2013-10-08", "2013-10-09"], freq="B")
+        tm.assert_index_equal(result, expected)
+
+    def test_integer_values_and_tz_interpreted_as_utc(self):
+        # GH-24559
+        val = np.datetime64("2000-01-01 00:00:00", "ns")
+        values = np.array([val.view("i8")])
+
+        result = DatetimeIndex(values).tz_localize("US/Central")
+
+        expected = DatetimeIndex(["2000-01-01T00:00:00"], dtype="M8[ns, US/Central]")
+        tm.assert_index_equal(result, expected)
+
+        # but UTC is *not* deprecated.
+        with tm.assert_produces_warning(None):
+            result = DatetimeIndex(values, tz="UTC")
+        expected = DatetimeIndex(["2000-01-01T00:00:00"], dtype="M8[ns, UTC]")
+        tm.assert_index_equal(result, expected)
+
+    def test_constructor_coverage(self):
+        msg = r"DatetimeIndex\(\.\.\.\) must be called with a collection"
+        with pytest.raises(TypeError, match=msg):
+            DatetimeIndex("1/1/2000")
+
+        # generator expression
+        gen = (datetime(2000, 1, 1) + timedelta(i) for i in range(10))
+        result = DatetimeIndex(gen)
+        expected = DatetimeIndex(
+            [datetime(2000, 1, 1) + timedelta(i) for i in range(10)]
+        )
+        tm.assert_index_equal(result, expected)
+
+        # NumPy string array
+        strings = np.array(["2000-01-01", "2000-01-02", "2000-01-03"])
+        result = DatetimeIndex(strings)
+        expected = DatetimeIndex(strings.astype("O"))
+        tm.assert_index_equal(result, expected)
+
+        from_ints = DatetimeIndex(expected.asi8)
+        tm.assert_index_equal(from_ints, expected)
+
+        # string with NaT
+        strings = np.array(["2000-01-01", "2000-01-02", "NaT"])
+        result = DatetimeIndex(strings)
+        expected = DatetimeIndex(strings.astype("O"))
+        tm.assert_index_equal(result, expected)
+
+        from_ints = DatetimeIndex(expected.asi8)
+        tm.assert_index_equal(from_ints, expected)
+
+        # non-conforming
+        msg = (
+            "Inferred frequency None from passed values does not conform "
+            "to passed frequency D"
+        )
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex(["2000-01-01", "2000-01-02", "2000-01-04"], freq="D")
+
+    @pytest.mark.parametrize("freq", ["YS", "W-SUN"])
+    def test_constructor_datetime64_tzformat(self, freq):
+        # see GH#6572: ISO 8601 format results in stdlib timezone object
+        idx = date_range(
+            "2013-01-01T00:00:00-05:00", "2016-01-01T23:59:59-05:00", freq=freq
+        )
+        expected = date_range(
+            "2013-01-01T00:00:00",
+            "2016-01-01T23:59:59",
+            freq=freq,
+            tz=timezone(timedelta(minutes=-300)),
+        )
+        tm.assert_index_equal(idx, expected)
+        # Unable to use `US/Eastern` because of DST
+        expected_i8 = date_range(
+            "2013-01-01T00:00:00", "2016-01-01T23:59:59", freq=freq, tz="America/Lima"
+        )
+        tm.assert_numpy_array_equal(idx.asi8, expected_i8.asi8)
+
+        idx = date_range(
+            "2013-01-01T00:00:00+09:00", "2016-01-01T23:59:59+09:00", freq=freq
+        )
+        expected = date_range(
+            "2013-01-01T00:00:00",
+            "2016-01-01T23:59:59",
+            freq=freq,
+            tz=timezone(timedelta(minutes=540)),
+        )
+        tm.assert_index_equal(idx, expected)
+        expected_i8 = date_range(
+            "2013-01-01T00:00:00", "2016-01-01T23:59:59", freq=freq, tz="Asia/Tokyo"
+        )
+        tm.assert_numpy_array_equal(idx.asi8, expected_i8.asi8)
+
+        # Non ISO 8601 format results in dateutil.tz.tzoffset
+        idx = date_range("2013/1/1 0:00:00-5:00", "2016/1/1 23:59:59-5:00", freq=freq)
+        expected = date_range(
+            "2013-01-01T00:00:00",
+            "2016-01-01T23:59:59",
+            freq=freq,
+            tz=timezone(timedelta(minutes=-300)),
+        )
+        tm.assert_index_equal(idx, expected)
+        # Unable to use `US/Eastern` because of DST
+        expected_i8 = date_range(
+            "2013-01-01T00:00:00", "2016-01-01T23:59:59", freq=freq, tz="America/Lima"
+        )
+        tm.assert_numpy_array_equal(idx.asi8, expected_i8.asi8)
+
+        idx = date_range("2013/1/1 0:00:00+9:00", "2016/1/1 23:59:59+09:00", freq=freq)
+        expected = date_range(
+            "2013-01-01T00:00:00",
+            "2016-01-01T23:59:59",
+            freq=freq,
+            tz=timezone(timedelta(minutes=540)),
+        )
+        tm.assert_index_equal(idx, expected)
+        expected_i8 = date_range(
+            "2013-01-01T00:00:00", "2016-01-01T23:59:59", freq=freq, tz="Asia/Tokyo"
+        )
+        tm.assert_numpy_array_equal(idx.asi8, expected_i8.asi8)
+
+    def test_constructor_dtype(self):
+        # passing a dtype with a tz should localize
+        idx = DatetimeIndex(
+            ["2013-01-01", "2013-01-02"], dtype="datetime64[ns, US/Eastern]"
+        )
+        expected = (
+            DatetimeIndex(["2013-01-01", "2013-01-02"])
+            .as_unit("ns")
+            .tz_localize("US/Eastern")
+        )
+        tm.assert_index_equal(idx, expected)
+
+        idx = DatetimeIndex(["2013-01-01", "2013-01-02"], tz="US/Eastern").as_unit("ns")
+        tm.assert_index_equal(idx, expected)
+
+    def test_constructor_dtype_tz_mismatch_raises(self):
+        # if we already have a tz and its not the same, then raise
+        idx = DatetimeIndex(
+            ["2013-01-01", "2013-01-02"], dtype="datetime64[ns, US/Eastern]"
+        )
+
+        msg = (
+            "cannot supply both a tz and a timezone-naive dtype "
+            r"\(i\.e\. datetime64\[ns\]\)"
+        )
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex(idx, dtype="datetime64[ns]")
+
+        # this is effectively trying to convert tz's
+        msg = "data is already tz-aware US/Eastern, unable to set specified tz: CET"
+        with pytest.raises(TypeError, match=msg):
+            DatetimeIndex(idx, dtype="datetime64[ns, CET]")
+        msg = "cannot supply both a tz and a dtype with a tz"
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex(idx, tz="CET", dtype="datetime64[ns, US/Eastern]")
+
+        result = DatetimeIndex(idx, dtype="datetime64[ns, US/Eastern]")
+        tm.assert_index_equal(idx, result)
+
+    @pytest.mark.parametrize("dtype", [object, np.int32, np.int64])
+    def test_constructor_invalid_dtype_raises(self, dtype):
+        # GH 23986
+        msg = "Unexpected value for 'dtype'"
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex([1, 2], dtype=dtype)
+
+    def test_000constructor_resolution(self):
+        # 2252
+        t1 = Timestamp((1352934390 * 1000000000) + 1000000 + 1000 + 1)
+        idx = DatetimeIndex([t1])
+
+        assert idx.nanosecond[0] == t1.nanosecond
+
+    def test_disallow_setting_tz(self):
+        # GH 3746
+        dti = DatetimeIndex(["2010"], tz="UTC")
+        msg = "Cannot directly set timezone"
+        with pytest.raises(AttributeError, match=msg):
+            dti.tz = pytz.timezone("US/Pacific")
+
+    @pytest.mark.parametrize(
+        "tz",
+        [
+            None,
+            "America/Los_Angeles",
+            pytz.timezone("America/Los_Angeles"),
+            Timestamp("2000", tz="America/Los_Angeles").tz,
+        ],
+    )
+    def test_constructor_start_end_with_tz(self, tz):
+        # GH 18595
+        start = Timestamp("2013-01-01 06:00:00", tz="America/Los_Angeles")
+        end = Timestamp("2013-01-02 06:00:00", tz="America/Los_Angeles")
+        result = date_range(freq="D", start=start, end=end, tz=tz)
+        expected = DatetimeIndex(
+            ["2013-01-01 06:00:00", "2013-01-02 06:00:00"],
+            dtype="M8[ns, America/Los_Angeles]",
+            freq="D",
+        )
+        tm.assert_index_equal(result, expected)
+        # Especially assert that the timezone is consistent for pytz
+        assert pytz.timezone("America/Los_Angeles") is result.tz
+
+    @pytest.mark.parametrize("tz", ["US/Pacific", "US/Eastern", "Asia/Tokyo"])
+    def test_constructor_with_non_normalized_pytz(self, tz):
+        # GH 18595
+        non_norm_tz = Timestamp("2010", tz=tz).tz
+        result = DatetimeIndex(["2010"], tz=non_norm_tz)
+        assert pytz.timezone(tz) is result.tz
+
+    def test_constructor_timestamp_near_dst(self):
+        # GH 20854
+        ts = [
+            Timestamp("2016-10-30 03:00:00+0300", tz="Europe/Helsinki"),
+            Timestamp("2016-10-30 03:00:00+0200", tz="Europe/Helsinki"),
+        ]
+        result = DatetimeIndex(ts)
+        expected = DatetimeIndex([ts[0].to_pydatetime(), ts[1].to_pydatetime()])
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize("klass", [Index, DatetimeIndex])
+    @pytest.mark.parametrize("box", [np.array, partial(np.array, dtype=object), list])
+    @pytest.mark.parametrize(
+        "tz, dtype",
+        [("US/Pacific", "datetime64[ns, US/Pacific]"), (None, "datetime64[ns]")],
+    )
+    def test_constructor_with_int_tz(self, klass, box, tz, dtype):
+        # GH 20997, 20964
+        ts = Timestamp("2018-01-01", tz=tz).as_unit("ns")
+        result = klass(box([ts._value]), dtype=dtype)
+        expected = klass([ts])
+        assert result == expected
+
+    def test_construction_int_rountrip(self, tz_naive_fixture):
+        # GH 12619, GH#24559
+        tz = tz_naive_fixture
+
+        result = 1293858000000000000
+        expected = DatetimeIndex([result], tz=tz).asi8[0]
+        assert result == expected
+
+    def test_construction_from_replaced_timestamps_with_dst(self):
+        # GH 18785
+        index = date_range(
+            Timestamp(2000, 12, 31),
+            Timestamp(2005, 12, 31),
+            freq="YE-DEC",
+            tz="Australia/Melbourne",
+        )
+        result = DatetimeIndex([x.replace(month=6, day=1) for x in index])
+        expected = DatetimeIndex(
+            [
+                "2000-06-01 00:00:00",
+                "2001-06-01 00:00:00",
+                "2002-06-01 00:00:00",
+                "2003-06-01 00:00:00",
+                "2004-06-01 00:00:00",
+                "2005-06-01 00:00:00",
+            ],
+            tz="Australia/Melbourne",
+        )
+        tm.assert_index_equal(result, expected)
+
+    def test_construction_with_tz_and_tz_aware_dti(self):
+        # GH 23579
+        dti = date_range("2016-01-01", periods=3, tz="US/Central")
+        msg = "data is already tz-aware US/Central, unable to set specified tz"
+        with pytest.raises(TypeError, match=msg):
+            DatetimeIndex(dti, tz="Asia/Tokyo")
+
+    def test_construction_with_nat_and_tzlocal(self):
+        tz = dateutil.tz.tzlocal()
+        result = DatetimeIndex(["2018", "NaT"], tz=tz)
+        expected = DatetimeIndex([Timestamp("2018", tz=tz), pd.NaT])
+        tm.assert_index_equal(result, expected)
+
+    def test_constructor_with_ambiguous_keyword_arg(self):
+        # GH 35297
+
+        expected = DatetimeIndex(
+            ["2020-11-01 01:00:00", "2020-11-02 01:00:00"],
+            dtype="datetime64[ns, America/New_York]",
+            freq="D",
+            ambiguous=False,
+        )
+
+        # ambiguous keyword in start
+        timezone = "America/New_York"
+        start = Timestamp(year=2020, month=11, day=1, hour=1).tz_localize(
+            timezone, ambiguous=False
+        )
+        result = date_range(start=start, periods=2, ambiguous=False)
+        tm.assert_index_equal(result, expected)
+
+        # ambiguous keyword in end
+        timezone = "America/New_York"
+        end = Timestamp(year=2020, month=11, day=2, hour=1).tz_localize(
+            timezone, ambiguous=False
+        )
+        result = date_range(end=end, periods=2, ambiguous=False)
+        tm.assert_index_equal(result, expected)
+
+    def test_constructor_with_nonexistent_keyword_arg(self, warsaw):
+        # GH 35297
+        timezone = warsaw
+
+        # nonexistent keyword in start
+        start = Timestamp("2015-03-29 02:30:00").tz_localize(
+            timezone, nonexistent="shift_forward"
+        )
+        result = date_range(start=start, periods=2, freq="h")
+        expected = DatetimeIndex(
+            [
+                Timestamp("2015-03-29 03:00:00+02:00", tz=timezone),
+                Timestamp("2015-03-29 04:00:00+02:00", tz=timezone),
+            ]
+        )
+
+        tm.assert_index_equal(result, expected)
+
+        # nonexistent keyword in end
+        end = start
+        result = date_range(end=end, periods=2, freq="h")
+        expected = DatetimeIndex(
+            [
+                Timestamp("2015-03-29 01:00:00+01:00", tz=timezone),
+                Timestamp("2015-03-29 03:00:00+02:00", tz=timezone),
+            ]
+        )
+
+        tm.assert_index_equal(result, expected)
+
+    def test_constructor_no_precision_raises(self):
+        # GH-24753, GH-24739
+
+        msg = "with no precision is not allowed"
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex(["2000"], dtype="datetime64")
+
+        msg = "The 'datetime64' dtype has no unit. Please pass in"
+        with pytest.raises(ValueError, match=msg):
+            Index(["2000"], dtype="datetime64")
+
+    def test_constructor_wrong_precision_raises(self):
+        dti = DatetimeIndex(["2000"], dtype="datetime64[us]")
+        assert dti.dtype == "M8[us]"
+        assert dti[0] == Timestamp(2000, 1, 1)
+
+    def test_index_constructor_with_numpy_object_array_and_timestamp_tz_with_nan(self):
+        # GH 27011
+        result = Index(np.array([Timestamp("2019", tz="UTC"), np.nan], dtype=object))
+        expected = DatetimeIndex([Timestamp("2019", tz="UTC"), pd.NaT])
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize("tz", [pytz.timezone("US/Eastern"), gettz("US/Eastern")])
+    def test_dti_from_tzaware_datetime(self, tz):
+        d = [datetime(2012, 8, 19, tzinfo=tz)]
+
+        index = DatetimeIndex(d)
+        assert timezones.tz_compare(index.tz, tz)
+
+    @pytest.mark.parametrize("tzstr", ["US/Eastern", "dateutil/US/Eastern"])
+    def test_dti_tz_constructors(self, tzstr):
+        """Test different DatetimeIndex constructions with timezone
+        Follow-up of GH#4229
+        """
+        arr = ["11/10/2005 08:00:00", "11/10/2005 09:00:00"]
+
+        idx1 = to_datetime(arr).tz_localize(tzstr)
+        idx2 = date_range(start="2005-11-10 08:00:00", freq="h", periods=2, tz=tzstr)
+        idx2 = idx2._with_freq(None)  # the others all have freq=None
+        idx3 = DatetimeIndex(arr, tz=tzstr)
+        idx4 = DatetimeIndex(np.array(arr), tz=tzstr)
+
+        for other in [idx2, idx3, idx4]:
+            tm.assert_index_equal(idx1, other)
+
+    def test_dti_construction_idempotent(self, unit):
+        rng = date_range(
+            "03/12/2012 00:00", periods=10, freq="W-FRI", tz="US/Eastern", unit=unit
+        )
+        rng2 = DatetimeIndex(data=rng, tz="US/Eastern")
+        tm.assert_index_equal(rng, rng2)
+
+    @pytest.mark.parametrize("prefix", ["", "dateutil/"])
+    def test_dti_constructor_static_tzinfo(self, prefix):
+        # it works!
+        index = DatetimeIndex([datetime(2012, 1, 1)], tz=prefix + "EST")
+        index.hour
+        index[0]
+
+    @pytest.mark.parametrize("tzstr", ["US/Eastern", "dateutil/US/Eastern"])
+    def test_dti_convert_datetime_list(self, tzstr):
+        dr = date_range("2012-06-02", periods=10, tz=tzstr, name="foo")
+        dr2 = DatetimeIndex(list(dr), name="foo", freq="D")
+        tm.assert_index_equal(dr, dr2)
+
+    @pytest.mark.parametrize(
+        "tz",
+        [
+            pytz.timezone("US/Eastern"),
+            gettz("US/Eastern"),
+        ],
+    )
+    @pytest.mark.parametrize("use_str", [True, False])
+    @pytest.mark.parametrize("box_cls", [Timestamp, DatetimeIndex])
+    def test_dti_ambiguous_matches_timestamp(self, tz, use_str, box_cls, request):
+        # GH#47471 check that we get the same raising behavior in the DTI
+        # constructor and Timestamp constructor
+        dtstr = "2013-11-03 01:59:59.999999"
+        item = dtstr
+        if not use_str:
+            item = Timestamp(dtstr).to_pydatetime()
+        if box_cls is not Timestamp:
+            item = [item]
+
+        if not use_str and isinstance(tz, dateutil.tz.tzfile):
+            # FIXME: The Timestamp constructor here behaves differently than all
+            #  the other cases bc with dateutil/zoneinfo tzinfos we implicitly
+            #  get fold=0. Having this raise is not important, but having the
+            #  behavior be consistent across cases is.
+            mark = pytest.mark.xfail(reason="We implicitly get fold=0.")
+            request.applymarker(mark)
+
+        with pytest.raises(pytz.AmbiguousTimeError, match=dtstr):
+            box_cls(item, tz=tz)
+
+    @pytest.mark.parametrize("tz", [None, "UTC", "US/Pacific"])
+    def test_dti_constructor_with_non_nano_dtype(self, tz):
+        # GH#55756, GH#54620
+        ts = Timestamp("2999-01-01")
+        dtype = "M8[us]"
+        if tz is not None:
+            dtype = f"M8[us, {tz}]"
+        vals = [ts, "2999-01-02 03:04:05.678910", 2500]
+        result = DatetimeIndex(vals, dtype=dtype)
+        # The 2500 is interpreted as microseconds, consistent with what
+        #  we would get if we created DatetimeIndexes from vals[:2] and vals[2:]
+        #  and concated the results.
+        pointwise = [
+            vals[0].tz_localize(tz),
+            Timestamp(vals[1], tz=tz),
+            to_datetime(vals[2], unit="us", utc=True).tz_convert(tz),
+        ]
+        exp_vals = [x.as_unit("us").asm8 for x in pointwise]
+        exp_arr = np.array(exp_vals, dtype="M8[us]")
+        expected = DatetimeIndex(exp_arr, dtype="M8[us]")
+        if tz is not None:
+            expected = expected.tz_localize("UTC").tz_convert(tz)
+        tm.assert_index_equal(result, expected)
+
+        result2 = DatetimeIndex(np.array(vals, dtype=object), dtype=dtype)
+        tm.assert_index_equal(result2, expected)
+
+    def test_dti_constructor_with_non_nano_now_today(self):
+        # GH#55756
+        now = Timestamp.now()
+        today = Timestamp.today()
+        result = DatetimeIndex(["now", "today"], dtype="M8[s]")
+        assert result.dtype == "M8[s]"
+
+        # result may not exactly match [now, today] so we'll test it up to a tolerance.
+        #  (it *may* match exactly due to rounding)
+        tolerance = pd.Timedelta(microseconds=1)
+
+        diff0 = result[0] - now.as_unit("s")
+        assert diff0 >= pd.Timedelta(0)
+        assert diff0 < tolerance
+
+        diff1 = result[1] - today.as_unit("s")
+        assert diff1 >= pd.Timedelta(0)
+        assert diff1 < tolerance
+
+    def test_dti_constructor_object_float_matches_float_dtype(self):
+        # GH#55780
+        arr = np.array([0, np.nan], dtype=np.float64)
+        arr2 = arr.astype(object)
+
+        dti1 = DatetimeIndex(arr, tz="CET")
+        dti2 = DatetimeIndex(arr2, tz="CET")
+        tm.assert_index_equal(dti1, dti2)
+
+    @pytest.mark.parametrize("dtype", ["M8[us]", "M8[us, US/Pacific]"])
+    def test_dti_constructor_with_dtype_object_int_matches_int_dtype(self, dtype):
+        # Going through the object path should match the non-object path
+
+        vals1 = np.arange(5, dtype="i8") * 1000
+        vals1[0] = pd.NaT.value
+
+        vals2 = vals1.astype(np.float64)
+        vals2[0] = np.nan
+
+        vals3 = vals1.astype(object)
+        # change lib.infer_dtype(vals3) from "integer" so we go through
+        #  array_to_datetime in _sequence_to_dt64
+        vals3[0] = pd.NaT
+
+        vals4 = vals2.astype(object)
+
+        res1 = DatetimeIndex(vals1, dtype=dtype)
+        res2 = DatetimeIndex(vals2, dtype=dtype)
+        res3 = DatetimeIndex(vals3, dtype=dtype)
+        res4 = DatetimeIndex(vals4, dtype=dtype)
+
+        expected = DatetimeIndex(vals1.view("M8[us]"))
+        if res1.tz is not None:
+            expected = expected.tz_localize("UTC").tz_convert(res1.tz)
+        tm.assert_index_equal(res1, expected)
+        tm.assert_index_equal(res2, expected)
+        tm.assert_index_equal(res3, expected)
+        tm.assert_index_equal(res4, expected)
+
+
+class TestTimeSeries:
+    def test_dti_constructor_preserve_dti_freq(self):
+        rng = date_range("1/1/2000", "1/2/2000", freq="5min")
+
+        rng2 = DatetimeIndex(rng)
+        assert rng.freq == rng2.freq
+
+    def test_explicit_none_freq(self):
+        # Explicitly passing freq=None is respected
+        rng = date_range("1/1/2000", "1/2/2000", freq="5min")
+
+        result = DatetimeIndex(rng, freq=None)
+        assert result.freq is None
+
+        result = DatetimeIndex(rng._data, freq=None)
+        assert result.freq is None
+
+    def test_dti_constructor_small_int(self, any_int_numpy_dtype):
+        # see gh-13721
+        exp = DatetimeIndex(
+            [
+                "1970-01-01 00:00:00.00000000",
+                "1970-01-01 00:00:00.00000001",
+                "1970-01-01 00:00:00.00000002",
+            ]
+        )
+
+        arr = np.array([0, 10, 20], dtype=any_int_numpy_dtype)
+        tm.assert_index_equal(DatetimeIndex(arr), exp)
+
+    def test_ctor_str_intraday(self):
+        rng = DatetimeIndex(["1-1-2000 00:00:01"])
+        assert rng[0].second == 1
+
+    def test_index_cast_datetime64_other_units(self):
+        arr = np.arange(0, 100, 10, dtype=np.int64).view("M8[D]")
+        idx = Index(arr)
+
+        assert (idx.values == astype_overflowsafe(arr, dtype=np.dtype("M8[ns]"))).all()
+
+    def test_constructor_int64_nocopy(self):
+        # GH#1624
+        arr = np.arange(1000, dtype=np.int64)
+        index = DatetimeIndex(arr)
+
+        arr[50:100] = -1
+        assert (index.asi8[50:100] == -1).all()
+
+        arr = np.arange(1000, dtype=np.int64)
+        index = DatetimeIndex(arr, copy=True)
+
+        arr[50:100] = -1
+        assert (index.asi8[50:100] != -1).all()
+
+    @pytest.mark.parametrize(
+        "freq",
+        ["ME", "QE", "YE", "D", "B", "bh", "min", "s", "ms", "us", "h", "ns", "C"],
+    )
+    def test_from_freq_recreate_from_data(self, freq):
+        org = date_range(start="2001/02/01 09:00", freq=freq, periods=1)
+        idx = DatetimeIndex(org, freq=freq)
+        tm.assert_index_equal(idx, org)
+
+        org = date_range(
+            start="2001/02/01 09:00", freq=freq, tz="US/Pacific", periods=1
+        )
+        idx = DatetimeIndex(org, freq=freq, tz="US/Pacific")
+        tm.assert_index_equal(idx, org)
+
+    def test_datetimeindex_constructor_misc(self):
+        arr = ["1/1/2005", "1/2/2005", "Jn 3, 2005", "2005-01-04"]
+        msg = r"(\(')?Unknown datetime string format(:', 'Jn 3, 2005'\))?"
+        with pytest.raises(ValueError, match=msg):
+            DatetimeIndex(arr)
+
+        arr = ["1/1/2005", "1/2/2005", "1/3/2005", "2005-01-04"]
+        idx1 = DatetimeIndex(arr)
+
+        arr = [datetime(2005, 1, 1), "1/2/2005", "1/3/2005", "2005-01-04"]
+        idx2 = DatetimeIndex(arr)
+
+        arr = [Timestamp(datetime(2005, 1, 1)), "1/2/2005", "1/3/2005", "2005-01-04"]
+        idx3 = DatetimeIndex(arr)
+
+        arr = np.array(["1/1/2005", "1/2/2005", "1/3/2005", "2005-01-04"], dtype="O")
+        idx4 = DatetimeIndex(arr)
+
+        idx5 = DatetimeIndex(["12/05/2007", "25/01/2008"], dayfirst=True)
+        idx6 = DatetimeIndex(
+            ["2007/05/12", "2008/01/25"], dayfirst=False, yearfirst=True
+        )
+        tm.assert_index_equal(idx5, idx6)
+
+        for other in [idx2, idx3, idx4]:
+            assert (idx1.values == other.values).all()
+
+    def test_dti_constructor_object_dtype_dayfirst_yearfirst_with_tz(self):
+        # GH#55813
+        val = "5/10/16"
+
+        dfirst = Timestamp(2016, 10, 5, tz="US/Pacific")
+        yfirst = Timestamp(2005, 10, 16, tz="US/Pacific")
+
+        result1 = DatetimeIndex([val], tz="US/Pacific", dayfirst=True)
+        expected1 = DatetimeIndex([dfirst])
+        tm.assert_index_equal(result1, expected1)
+
+        result2 = DatetimeIndex([val], tz="US/Pacific", yearfirst=True)
+        expected2 = DatetimeIndex([yfirst])
+        tm.assert_index_equal(result2, expected2)

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_date_range.py

@@ -0,0 +1,1721 @@
+"""
+test date_range, bdate_range construction from the convenience range functions
+"""
+
+from datetime import (
+    datetime,
+    time,
+    timedelta,
+)
+import re
+
+import numpy as np
+import pytest
+import pytz
+from pytz import timezone
+
+from pandas._libs.tslibs import timezones
+from pandas._libs.tslibs.offsets import (
+    BDay,
+    CDay,
+    DateOffset,
+    MonthEnd,
+    prefix_mapping,
+)
+from pandas.errors import OutOfBoundsDatetime
+import pandas.util._test_decorators as td
+
+import pandas as pd
+from pandas import (
+    DataFrame,
+    DatetimeIndex,
+    Series,
+    Timedelta,
+    Timestamp,
+    bdate_range,
+    date_range,
+    offsets,
+)
+import pandas._testing as tm
+from pandas.core.arrays.datetimes import _generate_range as generate_range
+from pandas.tests.indexes.datetimes.test_timezones import (
+    FixedOffset,
+    fixed_off_no_name,
+)
+
+from pandas.tseries.holiday import USFederalHolidayCalendar
+
+START, END = datetime(2009, 1, 1), datetime(2010, 1, 1)
+
+
+def _get_expected_range(
+    begin_to_match,
+    end_to_match,
+    both_range,
+    inclusive_endpoints,
+):
+    """Helper to get expected range from a both inclusive range"""
+    left_match = begin_to_match == both_range[0]
+    right_match = end_to_match == both_range[-1]
+
+    if inclusive_endpoints == "left" and right_match:
+        expected_range = both_range[:-1]
+    elif inclusive_endpoints == "right" and left_match:
+        expected_range = both_range[1:]
+    elif inclusive_endpoints == "neither" and left_match and right_match:
+        expected_range = both_range[1:-1]
+    elif inclusive_endpoints == "neither" and right_match:
+        expected_range = both_range[:-1]
+    elif inclusive_endpoints == "neither" and left_match:
+        expected_range = both_range[1:]
+    elif inclusive_endpoints == "both":
+        expected_range = both_range[:]
+    else:
+        expected_range = both_range[:]
+
+    return expected_range
+
+
+class TestTimestampEquivDateRange:
+    # Older tests in TestTimeSeries constructed their `stamp` objects
+    # using `date_range` instead of the `Timestamp` constructor.
+    # TestTimestampEquivDateRange checks that these are equivalent in the
+    # pertinent cases.
+
+    def test_date_range_timestamp_equiv(self):
+        rng = date_range("20090415", "20090519", tz="US/Eastern")
+        stamp = rng[0]
+
+        ts = Timestamp("20090415", tz="US/Eastern")
+        assert ts == stamp
+
+    def test_date_range_timestamp_equiv_dateutil(self):
+        rng = date_range("20090415", "20090519", tz="dateutil/US/Eastern")
+        stamp = rng[0]
+
+        ts = Timestamp("20090415", tz="dateutil/US/Eastern")
+        assert ts == stamp
+
+    def test_date_range_timestamp_equiv_explicit_pytz(self):
+        rng = date_range("20090415", "20090519", tz=pytz.timezone("US/Eastern"))
+        stamp = rng[0]
+
+        ts = Timestamp("20090415", tz=pytz.timezone("US/Eastern"))
+        assert ts == stamp
+
+    @td.skip_if_windows
+    def test_date_range_timestamp_equiv_explicit_dateutil(self):
+        from pandas._libs.tslibs.timezones import dateutil_gettz as gettz
+
+        rng = date_range("20090415", "20090519", tz=gettz("US/Eastern"))
+        stamp = rng[0]
+
+        ts = Timestamp("20090415", tz=gettz("US/Eastern"))
+        assert ts == stamp
+
+    def test_date_range_timestamp_equiv_from_datetime_instance(self):
+        datetime_instance = datetime(2014, 3, 4)
+        # build a timestamp with a frequency, since then it supports
+        # addition/subtraction of integers
+        timestamp_instance = date_range(datetime_instance, periods=1, freq="D")[0]
+
+        ts = Timestamp(datetime_instance)
+        assert ts == timestamp_instance
+
+    def test_date_range_timestamp_equiv_preserve_frequency(self):
+        timestamp_instance = date_range("2014-03-05", periods=1, freq="D")[0]
+        ts = Timestamp("2014-03-05")
+
+        assert timestamp_instance == ts
+
+
+class TestDateRanges:
+    def test_date_range_name(self):
+        idx = date_range(start="2000-01-01", periods=1, freq="YE", name="TEST")
+        assert idx.name == "TEST"
+
+    def test_date_range_invalid_periods(self):
+        msg = "periods must be a number, got foo"
+        with pytest.raises(TypeError, match=msg):
+            date_range(start="1/1/2000", periods="foo", freq="D")
+
+    def test_date_range_fractional_period(self):
+        msg = "Non-integer 'periods' in pd.date_range, pd.timedelta_range"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            rng = date_range("1/1/2000", periods=10.5)
+        exp = date_range("1/1/2000", periods=10)
+        tm.assert_index_equal(rng, exp)
+
+    @pytest.mark.parametrize(
+        "freq,freq_depr",
+        [
+            ("2ME", "2M"),
+            ("2SME", "2SM"),
+            ("2BQE", "2BQ"),
+            ("2BYE", "2BY"),
+        ],
+    )
+    def test_date_range_frequency_M_SM_BQ_BY_deprecated(self, freq, freq_depr):
+        # GH#52064
+        depr_msg = f"'{freq_depr[1:]}' is deprecated and will be removed "
+        f"in a future version, please use '{freq[1:]}' instead."
+
+        expected = date_range("1/1/2000", periods=4, freq=freq)
+        with tm.assert_produces_warning(FutureWarning, match=depr_msg):
+            result = date_range("1/1/2000", periods=4, freq=freq_depr)
+        tm.assert_index_equal(result, expected)
+
+    def test_date_range_tuple_freq_raises(self):
+        # GH#34703
+        edate = datetime(2000, 1, 1)
+        with pytest.raises(TypeError, match="pass as a string instead"):
+            date_range(end=edate, freq=("D", 5), periods=20)
+
+    @pytest.mark.parametrize("freq", ["ns", "us", "ms", "min", "s", "h", "D"])
+    def test_date_range_edges(self, freq):
+        # GH#13672
+        td = Timedelta(f"1{freq}")
+        ts = Timestamp("1970-01-01")
+
+        idx = date_range(
+            start=ts + td,
+            end=ts + 4 * td,
+            freq=freq,
+        )
+        exp = DatetimeIndex(
+            [ts + n * td for n in range(1, 5)],
+            dtype="M8[ns]",
+            freq=freq,
+        )
+        tm.assert_index_equal(idx, exp)
+
+        # start after end
+        idx = date_range(
+            start=ts + 4 * td,
+            end=ts + td,
+            freq=freq,
+        )
+        exp = DatetimeIndex([], dtype="M8[ns]", freq=freq)
+        tm.assert_index_equal(idx, exp)
+
+        # start matches end
+        idx = date_range(
+            start=ts + td,
+            end=ts + td,
+            freq=freq,
+        )
+        exp = DatetimeIndex([ts + td], dtype="M8[ns]", freq=freq)
+        tm.assert_index_equal(idx, exp)
+
+    def test_date_range_near_implementation_bound(self):
+        # GH#???
+        freq = Timedelta(1)
+
+        with pytest.raises(OutOfBoundsDatetime, match="Cannot generate range with"):
+            date_range(end=Timestamp.min, periods=2, freq=freq)
+
+    def test_date_range_nat(self):
+        # GH#11587
+        msg = "Neither `start` nor `end` can be NaT"
+        with pytest.raises(ValueError, match=msg):
+            date_range(start="2016-01-01", end=pd.NaT, freq="D")
+        with pytest.raises(ValueError, match=msg):
+            date_range(start=pd.NaT, end="2016-01-01", freq="D")
+
+    def test_date_range_multiplication_overflow(self):
+        # GH#24255
+        # check that overflows in calculating `addend = periods * stride`
+        #  are caught
+        with tm.assert_produces_warning(None):
+            # we should _not_ be seeing a overflow RuntimeWarning
+            dti = date_range(start="1677-09-22", periods=213503, freq="D")
+
+        assert dti[0] == Timestamp("1677-09-22")
+        assert len(dti) == 213503
+
+        msg = "Cannot generate range with"
+        with pytest.raises(OutOfBoundsDatetime, match=msg):
+            date_range("1969-05-04", periods=200000000, freq="30000D")
+
+    def test_date_range_unsigned_overflow_handling(self):
+        # GH#24255
+        # case where `addend = periods * stride` overflows int64 bounds
+        #  but not uint64 bounds
+        dti = date_range(start="1677-09-22", end="2262-04-11", freq="D")
+
+        dti2 = date_range(start=dti[0], periods=len(dti), freq="D")
+        assert dti2.equals(dti)
+
+        dti3 = date_range(end=dti[-1], periods=len(dti), freq="D")
+        assert dti3.equals(dti)
+
+    def test_date_range_int64_overflow_non_recoverable(self):
+        # GH#24255
+        # case with start later than 1970-01-01, overflow int64 but not uint64
+        msg = "Cannot generate range with"
+        with pytest.raises(OutOfBoundsDatetime, match=msg):
+            date_range(start="1970-02-01", periods=106752 * 24, freq="h")
+
+        # case with end before 1970-01-01, overflow int64 but not uint64
+        with pytest.raises(OutOfBoundsDatetime, match=msg):
+            date_range(end="1969-11-14", periods=106752 * 24, freq="h")
+
+    @pytest.mark.slow
+    @pytest.mark.parametrize(
+        "s_ts, e_ts", [("2262-02-23", "1969-11-14"), ("1970-02-01", "1677-10-22")]
+    )
+    def test_date_range_int64_overflow_stride_endpoint_different_signs(
+        self, s_ts, e_ts
+    ):
+        # cases where stride * periods overflow int64 and stride/endpoint
+        #  have different signs
+        start = Timestamp(s_ts)
+        end = Timestamp(e_ts)
+
+        expected = date_range(start=start, end=end, freq="-1h")
+        assert expected[0] == start
+        assert expected[-1] == end
+
+        dti = date_range(end=end, periods=len(expected), freq="-1h")
+        tm.assert_index_equal(dti, expected)
+
+    def test_date_range_out_of_bounds(self):
+        # GH#14187
+        msg = "Cannot generate range"
+        with pytest.raises(OutOfBoundsDatetime, match=msg):
+            date_range("2016-01-01", periods=100000, freq="D")
+        with pytest.raises(OutOfBoundsDatetime, match=msg):
+            date_range(end="1763-10-12", periods=100000, freq="D")
+
+    def test_date_range_gen_error(self):
+        rng = date_range("1/1/2000 00:00", "1/1/2000 00:18", freq="5min")
+        assert len(rng) == 4
+
+    def test_date_range_normalize(self):
+        snap = datetime.today()
+        n = 50
+
+        rng = date_range(snap, periods=n, normalize=False, freq="2D")
+
+        offset = timedelta(2)
+        expected = DatetimeIndex(
+            [snap + i * offset for i in range(n)], dtype="M8[ns]", freq=offset
+        )
+
+        tm.assert_index_equal(rng, expected)
+
+        rng = date_range("1/1/2000 08:15", periods=n, normalize=False, freq="B")
+        the_time = time(8, 15)
+        for val in rng:
+            assert val.time() == the_time
+
+    def test_date_range_ambiguous_arguments(self):
+        # #2538
+        start = datetime(2011, 1, 1, 5, 3, 40)
+        end = datetime(2011, 1, 1, 8, 9, 40)
+
+        msg = (
+            "Of the four parameters: start, end, periods, and "
+            "freq, exactly three must be specified"
+        )
+        with pytest.raises(ValueError, match=msg):
+            date_range(start, end, periods=10, freq="s")
+
+    def test_date_range_convenience_periods(self, unit):
+        # GH 20808
+        result = date_range("2018-04-24", "2018-04-27", periods=3, unit=unit)
+        expected = DatetimeIndex(
+            ["2018-04-24 00:00:00", "2018-04-25 12:00:00", "2018-04-27 00:00:00"],
+            dtype=f"M8[{unit}]",
+            freq=None,
+        )
+
+        tm.assert_index_equal(result, expected)
+
+        # Test if spacing remains linear if tz changes to dst in range
+        result = date_range(
+            "2018-04-01 01:00:00",
+            "2018-04-01 04:00:00",
+            tz="Australia/Sydney",
+            periods=3,
+            unit=unit,
+        )
+        expected = DatetimeIndex(
+            [
+                Timestamp("2018-04-01 01:00:00+1100", tz="Australia/Sydney"),
+                Timestamp("2018-04-01 02:00:00+1000", tz="Australia/Sydney"),
+                Timestamp("2018-04-01 04:00:00+1000", tz="Australia/Sydney"),
+            ]
+        ).as_unit(unit)
+        tm.assert_index_equal(result, expected)
+
+    def test_date_range_index_comparison(self):
+        rng = date_range("2011-01-01", periods=3, tz="US/Eastern")
+        df = Series(rng).to_frame()
+        arr = np.array([rng.to_list()]).T
+        arr2 = np.array([rng]).T
+
+        with pytest.raises(ValueError, match="Unable to coerce to Series"):
+            rng == df
+
+        with pytest.raises(ValueError, match="Unable to coerce to Series"):
+            df == rng
+
+        expected = DataFrame([True, True, True])
+
+        results = df == arr2
+        tm.assert_frame_equal(results, expected)
+
+        expected = Series([True, True, True], name=0)
+
+        results = df[0] == arr2[:, 0]
+        tm.assert_series_equal(results, expected)
+
+        expected = np.array(
+            [[True, False, False], [False, True, False], [False, False, True]]
+        )
+        results = rng == arr
+        tm.assert_numpy_array_equal(results, expected)
+
+    @pytest.mark.parametrize(
+        "start,end,result_tz",
+        [
+            ["20180101", "20180103", "US/Eastern"],
+            [datetime(2018, 1, 1), datetime(2018, 1, 3), "US/Eastern"],
+            [Timestamp("20180101"), Timestamp("20180103"), "US/Eastern"],
+            [
+                Timestamp("20180101", tz="US/Eastern"),
+                Timestamp("20180103", tz="US/Eastern"),
+                "US/Eastern",
+            ],
+            [
+                Timestamp("20180101", tz="US/Eastern"),
+                Timestamp("20180103", tz="US/Eastern"),
+                None,
+            ],
+        ],
+    )
+    def test_date_range_linspacing_tz(self, start, end, result_tz):
+        # GH 20983
+        result = date_range(start, end, periods=3, tz=result_tz)
+        expected = date_range("20180101", periods=3, freq="D", tz="US/Eastern")
+        tm.assert_index_equal(result, expected)
+
+    def test_date_range_timedelta(self):
+        start = "2020-01-01"
+        end = "2020-01-11"
+        rng1 = date_range(start, end, freq="3D")
+        rng2 = date_range(start, end, freq=timedelta(days=3))
+        tm.assert_index_equal(rng1, rng2)
+
+    def test_range_misspecified(self):
+        # GH #1095
+        msg = (
+            "Of the four parameters: start, end, periods, and "
+            "freq, exactly three must be specified"
+        )
+
+        with pytest.raises(ValueError, match=msg):
+            date_range(start="1/1/2000")
+
+        with pytest.raises(ValueError, match=msg):
+            date_range(end="1/1/2000")
+
+        with pytest.raises(ValueError, match=msg):
+            date_range(periods=10)
+
+        with pytest.raises(ValueError, match=msg):
+            date_range(start="1/1/2000", freq="h")
+
+        with pytest.raises(ValueError, match=msg):
+            date_range(end="1/1/2000", freq="h")
+
+        with pytest.raises(ValueError, match=msg):
+            date_range(periods=10, freq="h")
+
+        with pytest.raises(ValueError, match=msg):
+            date_range()
+
+    def test_compat_replace(self):
+        # https://github.com/statsmodels/statsmodels/issues/3349
+        # replace should take ints/longs for compat
+        result = date_range(Timestamp("1960-04-01 00:00:00"), periods=76, freq="QS-JAN")
+        assert len(result) == 76
+
+    def test_catch_infinite_loop(self):
+        offset = offsets.DateOffset(minute=5)
+        # blow up, don't loop forever
+        msg = "Offset <DateOffset: minute=5> did not increment date"
+        with pytest.raises(ValueError, match=msg):
+            date_range(datetime(2011, 11, 11), datetime(2011, 11, 12), freq=offset)
+
+    def test_construct_over_dst(self, unit):
+        # GH 20854
+        pre_dst = Timestamp("2010-11-07 01:00:00").tz_localize(
+            "US/Pacific", ambiguous=True
+        )
+        pst_dst = Timestamp("2010-11-07 01:00:00").tz_localize(
+            "US/Pacific", ambiguous=False
+        )
+        expect_data = [
+            Timestamp("2010-11-07 00:00:00", tz="US/Pacific"),
+            pre_dst,
+            pst_dst,
+        ]
+        expected = DatetimeIndex(expect_data, freq="h").as_unit(unit)
+        result = date_range(
+            start="2010-11-7", periods=3, freq="h", tz="US/Pacific", unit=unit
+        )
+        tm.assert_index_equal(result, expected)
+
+    def test_construct_with_different_start_end_string_format(self, unit):
+        # GH 12064
+        result = date_range(
+            "2013-01-01 00:00:00+09:00",
+            "2013/01/01 02:00:00+09:00",
+            freq="h",
+            unit=unit,
+        )
+        expected = DatetimeIndex(
+            [
+                Timestamp("2013-01-01 00:00:00+09:00"),
+                Timestamp("2013-01-01 01:00:00+09:00"),
+                Timestamp("2013-01-01 02:00:00+09:00"),
+            ],
+            freq="h",
+        ).as_unit(unit)
+        tm.assert_index_equal(result, expected)
+
+    def test_error_with_zero_monthends(self):
+        msg = r"Offset <0 \* MonthEnds> did not increment date"
+        with pytest.raises(ValueError, match=msg):
+            date_range("1/1/2000", "1/1/2001", freq=MonthEnd(0))
+
+    def test_range_bug(self, unit):
+        # GH #770
+        offset = DateOffset(months=3)
+        result = date_range("2011-1-1", "2012-1-31", freq=offset, unit=unit)
+
+        start = datetime(2011, 1, 1)
+        expected = DatetimeIndex(
+            [start + i * offset for i in range(5)], dtype=f"M8[{unit}]", freq=offset
+        )
+        tm.assert_index_equal(result, expected)
+
+    def test_range_tz_pytz(self):
+        # see gh-2906
+        tz = timezone("US/Eastern")
+        start = tz.localize(datetime(2011, 1, 1))
+        end = tz.localize(datetime(2011, 1, 3))
+
+        dr = date_range(start=start, periods=3)
+        assert dr.tz.zone == tz.zone
+        assert dr[0] == start
+        assert dr[2] == end
+
+        dr = date_range(end=end, periods=3)
+        assert dr.tz.zone == tz.zone
+        assert dr[0] == start
+        assert dr[2] == end
+
+        dr = date_range(start=start, end=end)
+        assert dr.tz.zone == tz.zone
+        assert dr[0] == start
+        assert dr[2] == end
+
+    @pytest.mark.parametrize(
+        "start, end",
+        [
+            [
+                Timestamp(datetime(2014, 3, 6), tz="US/Eastern"),
+                Timestamp(datetime(2014, 3, 12), tz="US/Eastern"),
+            ],
+            [
+                Timestamp(datetime(2013, 11, 1), tz="US/Eastern"),
+                Timestamp(datetime(2013, 11, 6), tz="US/Eastern"),
+            ],
+        ],
+    )
+    def test_range_tz_dst_straddle_pytz(self, start, end):
+        dr = date_range(start, end, freq="D")
+        assert dr[0] == start
+        assert dr[-1] == end
+        assert np.all(dr.hour == 0)
+
+        dr = date_range(start, end, freq="D", tz="US/Eastern")
+        assert dr[0] == start
+        assert dr[-1] == end
+        assert np.all(dr.hour == 0)
+
+        dr = date_range(
+            start.replace(tzinfo=None),
+            end.replace(tzinfo=None),
+            freq="D",
+            tz="US/Eastern",
+        )
+        assert dr[0] == start
+        assert dr[-1] == end
+        assert np.all(dr.hour == 0)
+
+    def test_range_tz_dateutil(self):
+        # see gh-2906
+
+        # Use maybe_get_tz to fix filename in tz under dateutil.
+        from pandas._libs.tslibs.timezones import maybe_get_tz
+
+        tz = lambda x: maybe_get_tz("dateutil/" + x)
+
+        start = datetime(2011, 1, 1, tzinfo=tz("US/Eastern"))
+        end = datetime(2011, 1, 3, tzinfo=tz("US/Eastern"))
+
+        dr = date_range(start=start, periods=3)
+        assert dr.tz == tz("US/Eastern")
+        assert dr[0] == start
+        assert dr[2] == end
+
+        dr = date_range(end=end, periods=3)
+        assert dr.tz == tz("US/Eastern")
+        assert dr[0] == start
+        assert dr[2] == end
+
+        dr = date_range(start=start, end=end)
+        assert dr.tz == tz("US/Eastern")
+        assert dr[0] == start
+        assert dr[2] == end
+
+    @pytest.mark.parametrize("freq", ["1D", "3D", "2ME", "7W", "3h", "YE"])
+    @pytest.mark.parametrize("tz", [None, "US/Eastern"])
+    def test_range_closed(self, freq, tz, inclusive_endpoints_fixture):
+        # GH#12409, GH#12684
+
+        begin = Timestamp("2011/1/1", tz=tz)
+        end = Timestamp("2014/1/1", tz=tz)
+
+        result_range = date_range(
+            begin, end, inclusive=inclusive_endpoints_fixture, freq=freq
+        )
+        both_range = date_range(begin, end, inclusive="both", freq=freq)
+        expected_range = _get_expected_range(
+            begin, end, both_range, inclusive_endpoints_fixture
+        )
+
+        tm.assert_index_equal(expected_range, result_range)
+
+    @pytest.mark.parametrize("freq", ["1D", "3D", "2ME", "7W", "3h", "YE"])
+    def test_range_with_tz_closed_with_tz_aware_start_end(
+        self, freq, inclusive_endpoints_fixture
+    ):
+        begin = Timestamp("2011/1/1")
+        end = Timestamp("2014/1/1")
+        begintz = Timestamp("2011/1/1", tz="US/Eastern")
+        endtz = Timestamp("2014/1/1", tz="US/Eastern")
+
+        result_range = date_range(
+            begin,
+            end,
+            inclusive=inclusive_endpoints_fixture,
+            freq=freq,
+            tz="US/Eastern",
+        )
+        both_range = date_range(
+            begin, end, inclusive="both", freq=freq, tz="US/Eastern"
+        )
+        expected_range = _get_expected_range(
+            begintz,
+            endtz,
+            both_range,
+            inclusive_endpoints_fixture,
+        )
+
+        tm.assert_index_equal(expected_range, result_range)
+
+    def test_range_closed_boundary(self, inclusive_endpoints_fixture):
+        # GH#11804
+        right_boundary = date_range(
+            "2015-09-12",
+            "2015-12-01",
+            freq="QS-MAR",
+            inclusive=inclusive_endpoints_fixture,
+        )
+        left_boundary = date_range(
+            "2015-09-01",
+            "2015-09-12",
+            freq="QS-MAR",
+            inclusive=inclusive_endpoints_fixture,
+        )
+        both_boundary = date_range(
+            "2015-09-01",
+            "2015-12-01",
+            freq="QS-MAR",
+            inclusive=inclusive_endpoints_fixture,
+        )
+        neither_boundary = date_range(
+            "2015-09-11",
+            "2015-09-12",
+            freq="QS-MAR",
+            inclusive=inclusive_endpoints_fixture,
+        )
+
+        expected_right = both_boundary
+        expected_left = both_boundary
+        expected_both = both_boundary
+
+        if inclusive_endpoints_fixture == "right":
+            expected_left = both_boundary[1:]
+        elif inclusive_endpoints_fixture == "left":
+            expected_right = both_boundary[:-1]
+        elif inclusive_endpoints_fixture == "both":
+            expected_right = both_boundary[1:]
+            expected_left = both_boundary[:-1]
+
+        expected_neither = both_boundary[1:-1]
+
+        tm.assert_index_equal(right_boundary, expected_right)
+        tm.assert_index_equal(left_boundary, expected_left)
+        tm.assert_index_equal(both_boundary, expected_both)
+        tm.assert_index_equal(neither_boundary, expected_neither)
+
+    def test_date_range_years_only(self, tz_naive_fixture):
+        tz = tz_naive_fixture
+        # GH#6961
+        rng1 = date_range("2014", "2015", freq="ME", tz=tz)
+        expected1 = date_range("2014-01-31", "2014-12-31", freq="ME", tz=tz)
+        tm.assert_index_equal(rng1, expected1)
+
+        rng2 = date_range("2014", "2015", freq="MS", tz=tz)
+        expected2 = date_range("2014-01-01", "2015-01-01", freq="MS", tz=tz)
+        tm.assert_index_equal(rng2, expected2)
+
+        rng3 = date_range("2014", "2020", freq="YE", tz=tz)
+        expected3 = date_range("2014-12-31", "2019-12-31", freq="YE", tz=tz)
+        tm.assert_index_equal(rng3, expected3)
+
+        rng4 = date_range("2014", "2020", freq="YS", tz=tz)
+        expected4 = date_range("2014-01-01", "2020-01-01", freq="YS", tz=tz)
+        tm.assert_index_equal(rng4, expected4)
+
+    def test_freq_divides_end_in_nanos(self):
+        # GH 10885
+        result_1 = date_range("2005-01-12 10:00", "2005-01-12 16:00", freq="345min")
+        result_2 = date_range("2005-01-13 10:00", "2005-01-13 16:00", freq="345min")
+        expected_1 = DatetimeIndex(
+            ["2005-01-12 10:00:00", "2005-01-12 15:45:00"],
+            dtype="datetime64[ns]",
+            freq="345min",
+            tz=None,
+        )
+        expected_2 = DatetimeIndex(
+            ["2005-01-13 10:00:00", "2005-01-13 15:45:00"],
+            dtype="datetime64[ns]",
+            freq="345min",
+            tz=None,
+        )
+        tm.assert_index_equal(result_1, expected_1)
+        tm.assert_index_equal(result_2, expected_2)
+
+    def test_cached_range_bug(self):
+        rng = date_range("2010-09-01 05:00:00", periods=50, freq=DateOffset(hours=6))
+        assert len(rng) == 50
+        assert rng[0] == datetime(2010, 9, 1, 5)
+
+    def test_timezone_comparison_bug(self):
+        # smoke test
+        start = Timestamp("20130220 10:00", tz="US/Eastern")
+        result = date_range(start, periods=2, tz="US/Eastern")
+        assert len(result) == 2
+
+    def test_timezone_comparison_assert(self):
+        start = Timestamp("20130220 10:00", tz="US/Eastern")
+        msg = "Inferred time zone not equal to passed time zone"
+        with pytest.raises(AssertionError, match=msg):
+            date_range(start, periods=2, tz="Europe/Berlin")
+
+    def test_negative_non_tick_frequency_descending_dates(self, tz_aware_fixture):
+        # GH 23270
+        tz = tz_aware_fixture
+        result = date_range(start="2011-06-01", end="2011-01-01", freq="-1MS", tz=tz)
+        expected = date_range(end="2011-06-01", start="2011-01-01", freq="1MS", tz=tz)[
+            ::-1
+        ]
+        tm.assert_index_equal(result, expected)
+
+    def test_range_where_start_equal_end(self, inclusive_endpoints_fixture):
+        # GH 43394
+        start = "2021-09-02"
+        end = "2021-09-02"
+        result = date_range(
+            start=start, end=end, freq="D", inclusive=inclusive_endpoints_fixture
+        )
+
+        both_range = date_range(start=start, end=end, freq="D", inclusive="both")
+        if inclusive_endpoints_fixture == "neither":
+            expected = both_range[1:-1]
+        elif inclusive_endpoints_fixture in ("left", "right", "both"):
+            expected = both_range[:]
+
+        tm.assert_index_equal(result, expected)
+
+    def test_freq_dateoffset_with_relateivedelta_nanos(self):
+        # GH 46877
+        freq = DateOffset(hours=10, days=57, nanoseconds=3)
+        result = date_range(end="1970-01-01 00:00:00", periods=10, freq=freq, name="a")
+        expected = DatetimeIndex(
+            [
+                "1968-08-02T05:59:59.999999973",
+                "1968-09-28T15:59:59.999999976",
+                "1968-11-25T01:59:59.999999979",
+                "1969-01-21T11:59:59.999999982",
+                "1969-03-19T21:59:59.999999985",
+                "1969-05-16T07:59:59.999999988",
+                "1969-07-12T17:59:59.999999991",
+                "1969-09-08T03:59:59.999999994",
+                "1969-11-04T13:59:59.999999997",
+                "1970-01-01T00:00:00.000000000",
+            ],
+            name="a",
+        )
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "freq,freq_depr",
+        [
+            ("h", "H"),
+            ("2min", "2T"),
+            ("1s", "1S"),
+            ("2ms", "2L"),
+            ("1us", "1U"),
+            ("2ns", "2N"),
+        ],
+    )
+    def test_frequencies_H_T_S_L_U_N_deprecated(self, freq, freq_depr):
+        # GH#52536
+        freq_msg = re.split("[0-9]*", freq, maxsplit=1)[1]
+        freq_depr_msg = re.split("[0-9]*", freq_depr, maxsplit=1)[1]
+        msg = (
+            f"'{freq_depr_msg}' is deprecated and will be removed in a future version, "
+        )
+        f"please use '{freq_msg}' instead"
+
+        expected = date_range("1/1/2000", periods=2, freq=freq)
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            result = date_range("1/1/2000", periods=2, freq=freq_depr)
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "freq,freq_depr",
+        [
+            ("200YE", "200A"),
+            ("YE", "Y"),
+            ("2YE-MAY", "2A-MAY"),
+            ("YE-MAY", "Y-MAY"),
+        ],
+    )
+    def test_frequencies_A_deprecated_Y_renamed(self, freq, freq_depr):
+        # GH#9586, GH#54275
+        freq_msg = re.split("[0-9]*", freq, maxsplit=1)[1]
+        freq_depr_msg = re.split("[0-9]*", freq_depr, maxsplit=1)[1]
+        msg = f"'{freq_depr_msg}' is deprecated and will be removed "
+        f"in a future version, please use '{freq_msg}' instead."
+
+        expected = date_range("1/1/2000", periods=2, freq=freq)
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            result = date_range("1/1/2000", periods=2, freq=freq_depr)
+        tm.assert_index_equal(result, expected)
+
+    def test_to_offset_with_lowercase_deprecated_freq(self) -> None:
+        # https://github.com/pandas-dev/pandas/issues/56847
+        msg = (
+            "'m' is deprecated and will be removed in a future version, please use "
+            "'ME' instead."
+        )
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            result = date_range("2010-01-01", periods=2, freq="m")
+        expected = DatetimeIndex(["2010-01-31", "2010-02-28"], freq="ME")
+        tm.assert_index_equal(result, expected)
+
+    def test_date_range_bday(self):
+        sdate = datetime(1999, 12, 25)
+        idx = date_range(start=sdate, freq="1B", periods=20)
+        assert len(idx) == 20
+        assert idx[0] == sdate + 0 * offsets.BDay()
+        assert idx.freq == "B"
+
+
+class TestDateRangeTZ:
+    """Tests for date_range with timezones"""
+
+    def test_hongkong_tz_convert(self):
+        # GH#1673 smoke test
+        dr = date_range("2012-01-01", "2012-01-10", freq="D", tz="Hongkong")
+
+        # it works!
+        dr.hour
+
+    @pytest.mark.parametrize("tzstr", ["US/Eastern", "dateutil/US/Eastern"])
+    def test_date_range_span_dst_transition(self, tzstr):
+        # GH#1778
+
+        # Standard -> Daylight Savings Time
+        dr = date_range("03/06/2012 00:00", periods=200, freq="W-FRI", tz="US/Eastern")
+
+        assert (dr.hour == 0).all()
+
+        dr = date_range("2012-11-02", periods=10, tz=tzstr)
+        result = dr.hour
+        expected = pd.Index([0] * 10, dtype="int32")
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize("tzstr", ["US/Eastern", "dateutil/US/Eastern"])
+    def test_date_range_timezone_str_argument(self, tzstr):
+        tz = timezones.maybe_get_tz(tzstr)
+        result = date_range("1/1/2000", periods=10, tz=tzstr)
+        expected = date_range("1/1/2000", periods=10, tz=tz)
+
+        tm.assert_index_equal(result, expected)
+
+    def test_date_range_with_fixed_tz(self):
+        off = FixedOffset(420, "+07:00")
+        start = datetime(2012, 3, 11, 5, 0, 0, tzinfo=off)
+        end = datetime(2012, 6, 11, 5, 0, 0, tzinfo=off)
+        rng = date_range(start=start, end=end)
+        assert off == rng.tz
+
+        rng2 = date_range(start, periods=len(rng), tz=off)
+        tm.assert_index_equal(rng, rng2)
+
+        rng3 = date_range("3/11/2012 05:00:00+07:00", "6/11/2012 05:00:00+07:00")
+        assert (rng.values == rng3.values).all()
+
+    def test_date_range_with_fixedoffset_noname(self):
+        off = fixed_off_no_name
+        start = datetime(2012, 3, 11, 5, 0, 0, tzinfo=off)
+        end = datetime(2012, 6, 11, 5, 0, 0, tzinfo=off)
+        rng = date_range(start=start, end=end)
+        assert off == rng.tz
+
+        idx = pd.Index([start, end])
+        assert off == idx.tz
+
+    @pytest.mark.parametrize("tzstr", ["US/Eastern", "dateutil/US/Eastern"])
+    def test_date_range_with_tz(self, tzstr):
+        stamp = Timestamp("3/11/2012 05:00", tz=tzstr)
+        assert stamp.hour == 5
+
+        rng = date_range("3/11/2012 04:00", periods=10, freq="h", tz=tzstr)
+
+        assert stamp == rng[1]
+
+    @pytest.mark.parametrize("tz", ["Europe/London", "dateutil/Europe/London"])
+    def test_date_range_ambiguous_endpoint(self, tz):
+        # construction with an ambiguous end-point
+        # GH#11626
+
+        with pytest.raises(pytz.AmbiguousTimeError, match="Cannot infer dst time"):
+            date_range(
+                "2013-10-26 23:00", "2013-10-27 01:00", tz="Europe/London", freq="h"
+            )
+
+        times = date_range(
+            "2013-10-26 23:00", "2013-10-27 01:00", freq="h", tz=tz, ambiguous="infer"
+        )
+        assert times[0] == Timestamp("2013-10-26 23:00", tz=tz)
+        assert times[-1] == Timestamp("2013-10-27 01:00:00+0000", tz=tz)
+
+    @pytest.mark.parametrize(
+        "tz, option, expected",
+        [
+            ["US/Pacific", "shift_forward", "2019-03-10 03:00"],
+            ["dateutil/US/Pacific", "shift_forward", "2019-03-10 03:00"],
+            ["US/Pacific", "shift_backward", "2019-03-10 01:00"],
+            ["dateutil/US/Pacific", "shift_backward", "2019-03-10 01:00"],
+            ["US/Pacific", timedelta(hours=1), "2019-03-10 03:00"],
+        ],
+    )
+    def test_date_range_nonexistent_endpoint(self, tz, option, expected):
+        # construction with an nonexistent end-point
+
+        with pytest.raises(pytz.NonExistentTimeError, match="2019-03-10 02:00:00"):
+            date_range(
+                "2019-03-10 00:00", "2019-03-10 02:00", tz="US/Pacific", freq="h"
+            )
+
+        times = date_range(
+            "2019-03-10 00:00", "2019-03-10 02:00", freq="h", tz=tz, nonexistent=option
+        )
+        assert times[-1] == Timestamp(expected, tz=tz)
+
+
+class TestGenRangeGeneration:
+    @pytest.mark.parametrize(
+        "freqstr,offset",
+        [
+            ("B", BDay()),
+            ("C", CDay()),
+        ],
+    )
+    def test_generate(self, freqstr, offset):
+        rng1 = list(generate_range(START, END, periods=None, offset=offset, unit="ns"))
+        rng2 = list(generate_range(START, END, periods=None, offset=freqstr, unit="ns"))
+        assert rng1 == rng2
+
+    def test_1(self):
+        rng = list(
+            generate_range(
+                start=datetime(2009, 3, 25),
+                end=None,
+                periods=2,
+                offset=BDay(),
+                unit="ns",
+            )
+        )
+        expected = [datetime(2009, 3, 25), datetime(2009, 3, 26)]
+        assert rng == expected
+
+    def test_2(self):
+        rng = list(
+            generate_range(
+                start=datetime(2008, 1, 1),
+                end=datetime(2008, 1, 3),
+                periods=None,
+                offset=BDay(),
+                unit="ns",
+            )
+        )
+        expected = [datetime(2008, 1, 1), datetime(2008, 1, 2), datetime(2008, 1, 3)]
+        assert rng == expected
+
+    def test_3(self):
+        rng = list(
+            generate_range(
+                start=datetime(2008, 1, 5),
+                end=datetime(2008, 1, 6),
+                periods=None,
+                offset=BDay(),
+                unit="ns",
+            )
+        )
+        expected = []
+        assert rng == expected
+
+    def test_precision_finer_than_offset(self):
+        # GH#9907
+        result1 = date_range(
+            start="2015-04-15 00:00:03", end="2016-04-22 00:00:00", freq="QE"
+        )
+        result2 = date_range(
+            start="2015-04-15 00:00:03", end="2015-06-22 00:00:04", freq="W"
+        )
+        expected1_list = [
+            "2015-06-30 00:00:03",
+            "2015-09-30 00:00:03",
+            "2015-12-31 00:00:03",
+            "2016-03-31 00:00:03",
+        ]
+        expected2_list = [
+            "2015-04-19 00:00:03",
+            "2015-04-26 00:00:03",
+            "2015-05-03 00:00:03",
+            "2015-05-10 00:00:03",
+            "2015-05-17 00:00:03",
+            "2015-05-24 00:00:03",
+            "2015-05-31 00:00:03",
+            "2015-06-07 00:00:03",
+            "2015-06-14 00:00:03",
+            "2015-06-21 00:00:03",
+        ]
+        expected1 = DatetimeIndex(
+            expected1_list, dtype="datetime64[ns]", freq="QE-DEC", tz=None
+        )
+        expected2 = DatetimeIndex(
+            expected2_list, dtype="datetime64[ns]", freq="W-SUN", tz=None
+        )
+        tm.assert_index_equal(result1, expected1)
+        tm.assert_index_equal(result2, expected2)
+
+    dt1, dt2 = "2017-01-01", "2017-01-01"
+    tz1, tz2 = "US/Eastern", "Europe/London"
+
+    @pytest.mark.parametrize(
+        "start,end",
+        [
+            (Timestamp(dt1, tz=tz1), Timestamp(dt2)),
+            (Timestamp(dt1), Timestamp(dt2, tz=tz2)),
+            (Timestamp(dt1, tz=tz1), Timestamp(dt2, tz=tz2)),
+            (Timestamp(dt1, tz=tz2), Timestamp(dt2, tz=tz1)),
+        ],
+    )
+    def test_mismatching_tz_raises_err(self, start, end):
+        # issue 18488
+        msg = "Start and end cannot both be tz-aware with different timezones"
+        with pytest.raises(TypeError, match=msg):
+            date_range(start, end)
+        with pytest.raises(TypeError, match=msg):
+            date_range(start, end, freq=BDay())
+
+
+class TestBusinessDateRange:
+    def test_constructor(self):
+        bdate_range(START, END, freq=BDay())
+        bdate_range(START, periods=20, freq=BDay())
+        bdate_range(end=START, periods=20, freq=BDay())
+
+        msg = "periods must be a number, got B"
+        with pytest.raises(TypeError, match=msg):
+            date_range("2011-1-1", "2012-1-1", "B")
+
+        with pytest.raises(TypeError, match=msg):
+            bdate_range("2011-1-1", "2012-1-1", "B")
+
+        msg = "freq must be specified for bdate_range; use date_range instead"
+        with pytest.raises(TypeError, match=msg):
+            bdate_range(START, END, periods=10, freq=None)
+
+    def test_misc(self):
+        end = datetime(2009, 5, 13)
+        dr = bdate_range(end=end, periods=20)
+        firstDate = end - 19 * BDay()
+
+        assert len(dr) == 20
+        assert dr[0] == firstDate
+        assert dr[-1] == end
+
+    def test_date_parse_failure(self):
+        badly_formed_date = "2007/100/1"
+
+        msg = "Unknown datetime string format, unable to parse: 2007/100/1"
+        with pytest.raises(ValueError, match=msg):
+            Timestamp(badly_formed_date)
+
+        with pytest.raises(ValueError, match=msg):
+            bdate_range(start=badly_formed_date, periods=10)
+
+        with pytest.raises(ValueError, match=msg):
+            bdate_range(end=badly_formed_date, periods=10)
+
+        with pytest.raises(ValueError, match=msg):
+            bdate_range(badly_formed_date, badly_formed_date)
+
+    def test_daterange_bug_456(self):
+        # GH #456
+        rng1 = bdate_range("12/5/2011", "12/5/2011")
+        rng2 = bdate_range("12/2/2011", "12/5/2011")
+        assert rng2._data.freq == BDay()
+
+        result = rng1.union(rng2)
+        assert isinstance(result, DatetimeIndex)
+
+    @pytest.mark.parametrize("inclusive", ["left", "right", "neither", "both"])
+    def test_bdays_and_open_boundaries(self, inclusive):
+        # GH 6673
+        start = "2018-07-21"  # Saturday
+        end = "2018-07-29"  # Sunday
+        result = date_range(start, end, freq="B", inclusive=inclusive)
+
+        bday_start = "2018-07-23"  # Monday
+        bday_end = "2018-07-27"  # Friday
+        expected = date_range(bday_start, bday_end, freq="D")
+        tm.assert_index_equal(result, expected)
+        # Note: we do _not_ expect the freqs to match here
+
+    def test_bday_near_overflow(self):
+        # GH#24252 avoid doing unnecessary addition that _would_ overflow
+        start = Timestamp.max.floor("D").to_pydatetime()
+        rng = date_range(start, end=None, periods=1, freq="B")
+        expected = DatetimeIndex([start], freq="B").as_unit("ns")
+        tm.assert_index_equal(rng, expected)
+
+    def test_bday_overflow_error(self):
+        # GH#24252 check that we get OutOfBoundsDatetime and not OverflowError
+        msg = "Out of bounds nanosecond timestamp"
+        start = Timestamp.max.floor("D").to_pydatetime()
+        with pytest.raises(OutOfBoundsDatetime, match=msg):
+            date_range(start, periods=2, freq="B")
+
+
+class TestCustomDateRange:
+    def test_constructor(self):
+        bdate_range(START, END, freq=CDay())
+        bdate_range(START, periods=20, freq=CDay())
+        bdate_range(end=START, periods=20, freq=CDay())
+
+        msg = "periods must be a number, got C"
+        with pytest.raises(TypeError, match=msg):
+            date_range("2011-1-1", "2012-1-1", "C")
+
+        with pytest.raises(TypeError, match=msg):
+            bdate_range("2011-1-1", "2012-1-1", "C")
+
+    def test_misc(self):
+        end = datetime(2009, 5, 13)
+        dr = bdate_range(end=end, periods=20, freq="C")
+        firstDate = end - 19 * CDay()
+
+        assert len(dr) == 20
+        assert dr[0] == firstDate
+        assert dr[-1] == end
+
+    def test_daterange_bug_456(self):
+        # GH #456
+        rng1 = bdate_range("12/5/2011", "12/5/2011", freq="C")
+        rng2 = bdate_range("12/2/2011", "12/5/2011", freq="C")
+        assert rng2._data.freq == CDay()
+
+        result = rng1.union(rng2)
+        assert isinstance(result, DatetimeIndex)
+
+    def test_cdaterange(self, unit):
+        result = bdate_range("2013-05-01", periods=3, freq="C", unit=unit)
+        expected = DatetimeIndex(
+            ["2013-05-01", "2013-05-02", "2013-05-03"], dtype=f"M8[{unit}]", freq="C"
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq == expected.freq
+
+    def test_cdaterange_weekmask(self, unit):
+        result = bdate_range(
+            "2013-05-01", periods=3, freq="C", weekmask="Sun Mon Tue Wed Thu", unit=unit
+        )
+        expected = DatetimeIndex(
+            ["2013-05-01", "2013-05-02", "2013-05-05"],
+            dtype=f"M8[{unit}]",
+            freq=result.freq,
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq == expected.freq
+
+        # raise with non-custom freq
+        msg = (
+            "a custom frequency string is required when holidays or "
+            "weekmask are passed, got frequency B"
+        )
+        with pytest.raises(ValueError, match=msg):
+            bdate_range("2013-05-01", periods=3, weekmask="Sun Mon Tue Wed Thu")
+
+    def test_cdaterange_holidays(self, unit):
+        result = bdate_range(
+            "2013-05-01", periods=3, freq="C", holidays=["2013-05-01"], unit=unit
+        )
+        expected = DatetimeIndex(
+            ["2013-05-02", "2013-05-03", "2013-05-06"],
+            dtype=f"M8[{unit}]",
+            freq=result.freq,
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq == expected.freq
+
+        # raise with non-custom freq
+        msg = (
+            "a custom frequency string is required when holidays or "
+            "weekmask are passed, got frequency B"
+        )
+        with pytest.raises(ValueError, match=msg):
+            bdate_range("2013-05-01", periods=3, holidays=["2013-05-01"])
+
+    def test_cdaterange_weekmask_and_holidays(self, unit):
+        result = bdate_range(
+            "2013-05-01",
+            periods=3,
+            freq="C",
+            weekmask="Sun Mon Tue Wed Thu",
+            holidays=["2013-05-01"],
+            unit=unit,
+        )
+        expected = DatetimeIndex(
+            ["2013-05-02", "2013-05-05", "2013-05-06"],
+            dtype=f"M8[{unit}]",
+            freq=result.freq,
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq == expected.freq
+
+    def test_cdaterange_holidays_weekmask_requires_freqstr(self):
+        # raise with non-custom freq
+        msg = (
+            "a custom frequency string is required when holidays or "
+            "weekmask are passed, got frequency B"
+        )
+        with pytest.raises(ValueError, match=msg):
+            bdate_range(
+                "2013-05-01",
+                periods=3,
+                weekmask="Sun Mon Tue Wed Thu",
+                holidays=["2013-05-01"],
+            )
+
+    @pytest.mark.parametrize(
+        "freq", [freq for freq in prefix_mapping if freq.startswith("C")]
+    )
+    def test_all_custom_freq(self, freq):
+        # should not raise
+        bdate_range(
+            START, END, freq=freq, weekmask="Mon Wed Fri", holidays=["2009-03-14"]
+        )
+
+        bad_freq = freq + "FOO"
+        msg = f"invalid custom frequency string: {bad_freq}"
+        with pytest.raises(ValueError, match=msg):
+            bdate_range(START, END, freq=bad_freq)
+
+    @pytest.mark.parametrize(
+        "start_end",
+        [
+            ("2018-01-01T00:00:01.000Z", "2018-01-03T00:00:01.000Z"),
+            ("2018-01-01T00:00:00.010Z", "2018-01-03T00:00:00.010Z"),
+            ("2001-01-01T00:00:00.010Z", "2001-01-03T00:00:00.010Z"),
+        ],
+    )
+    def test_range_with_millisecond_resolution(self, start_end):
+        # https://github.com/pandas-dev/pandas/issues/24110
+        start, end = start_end
+        result = date_range(start=start, end=end, periods=2, inclusive="left")
+        expected = DatetimeIndex([start], dtype="M8[ns, UTC]")
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "start,period,expected",
+        [
+            ("2022-07-23 00:00:00+02:00", 1, ["2022-07-25 00:00:00+02:00"]),
+            ("2022-07-22 00:00:00+02:00", 1, ["2022-07-22 00:00:00+02:00"]),
+            (
+                "2022-07-22 00:00:00+02:00",
+                2,
+                ["2022-07-22 00:00:00+02:00", "2022-07-25 00:00:00+02:00"],
+            ),
+        ],
+    )
+    def test_range_with_timezone_and_custombusinessday(self, start, period, expected):
+        # GH49441
+        result = date_range(start=start, periods=period, freq="C")
+        expected = DatetimeIndex(expected).as_unit("ns")
+        tm.assert_index_equal(result, expected)
+
+
+class TestDateRangeNonNano:
+    def test_date_range_reso_validation(self):
+        msg = "'unit' must be one of 's', 'ms', 'us', 'ns'"
+        with pytest.raises(ValueError, match=msg):
+            date_range("2016-01-01", "2016-03-04", periods=3, unit="h")
+
+    def test_date_range_freq_higher_than_reso(self):
+        # freq being higher-resolution than reso is a problem
+        msg = "Use a lower freq or a higher unit instead"
+        with pytest.raises(ValueError, match=msg):
+            #    # TODO give a more useful or informative message?
+            date_range("2016-01-01", "2016-01-02", freq="ns", unit="ms")
+
+    def test_date_range_freq_matches_reso(self):
+        # GH#49106 matching reso is OK
+        dti = date_range("2016-01-01", "2016-01-01 00:00:01", freq="ms", unit="ms")
+        rng = np.arange(1_451_606_400_000, 1_451_606_401_001, dtype=np.int64)
+        expected = DatetimeIndex(rng.view("M8[ms]"), freq="ms")
+        tm.assert_index_equal(dti, expected)
+
+        dti = date_range("2016-01-01", "2016-01-01 00:00:01", freq="us", unit="us")
+        rng = np.arange(1_451_606_400_000_000, 1_451_606_401_000_001, dtype=np.int64)
+        expected = DatetimeIndex(rng.view("M8[us]"), freq="us")
+        tm.assert_index_equal(dti, expected)
+
+        dti = date_range("2016-01-01", "2016-01-01 00:00:00.001", freq="ns", unit="ns")
+        rng = np.arange(
+            1_451_606_400_000_000_000, 1_451_606_400_001_000_001, dtype=np.int64
+        )
+        expected = DatetimeIndex(rng.view("M8[ns]"), freq="ns")
+        tm.assert_index_equal(dti, expected)
+
+    def test_date_range_freq_lower_than_endpoints(self):
+        start = Timestamp("2022-10-19 11:50:44.719781")
+        end = Timestamp("2022-10-19 11:50:47.066458")
+
+        # start and end cannot be cast to "s" unit without lossy rounding,
+        #  so we do not allow this in date_range
+        with pytest.raises(ValueError, match="Cannot losslessly convert units"):
+            date_range(start, end, periods=3, unit="s")
+
+        # but we can losslessly cast to "us"
+        dti = date_range(start, end, periods=2, unit="us")
+        rng = np.array(
+            [start.as_unit("us")._value, end.as_unit("us")._value], dtype=np.int64
+        )
+        expected = DatetimeIndex(rng.view("M8[us]"))
+        tm.assert_index_equal(dti, expected)
+
+    def test_date_range_non_nano(self):
+        start = np.datetime64("1066-10-14")  # Battle of Hastings
+        end = np.datetime64("2305-07-13")  # Jean-Luc Picard's birthday
+
+        dti = date_range(start, end, freq="D", unit="s")
+        assert dti.freq == "D"
+        assert dti.dtype == "M8[s]"
+
+        exp = np.arange(
+            start.astype("M8[s]").view("i8"),
+            (end + 1).astype("M8[s]").view("i8"),
+            24 * 3600,
+        ).view("M8[s]")
+
+        tm.assert_numpy_array_equal(dti.to_numpy(), exp)
+
+
+class TestDateRangeNonTickFreq:
+    # Tests revolving around less-common (non-Tick) `freq` keywords.
+
+    def test_date_range_custom_business_month_begin(self, unit):
+        hcal = USFederalHolidayCalendar()
+        freq = offsets.CBMonthBegin(calendar=hcal)
+        dti = date_range(start="20120101", end="20130101", freq=freq, unit=unit)
+        assert all(freq.is_on_offset(x) for x in dti)
+
+        expected = DatetimeIndex(
+            [
+                "2012-01-03",
+                "2012-02-01",
+                "2012-03-01",
+                "2012-04-02",
+                "2012-05-01",
+                "2012-06-01",
+                "2012-07-02",
+                "2012-08-01",
+                "2012-09-04",
+                "2012-10-01",
+                "2012-11-01",
+                "2012-12-03",
+            ],
+            dtype=f"M8[{unit}]",
+            freq=freq,
+        )
+        tm.assert_index_equal(dti, expected)
+
+    def test_date_range_custom_business_month_end(self, unit):
+        hcal = USFederalHolidayCalendar()
+        freq = offsets.CBMonthEnd(calendar=hcal)
+        dti = date_range(start="20120101", end="20130101", freq=freq, unit=unit)
+        assert all(freq.is_on_offset(x) for x in dti)
+
+        expected = DatetimeIndex(
+            [
+                "2012-01-31",
+                "2012-02-29",
+                "2012-03-30",
+                "2012-04-30",
+                "2012-05-31",
+                "2012-06-29",
+                "2012-07-31",
+                "2012-08-31",
+                "2012-09-28",
+                "2012-10-31",
+                "2012-11-30",
+                "2012-12-31",
+            ],
+            dtype=f"M8[{unit}]",
+            freq=freq,
+        )
+        tm.assert_index_equal(dti, expected)
+
+    def test_date_range_with_custom_holidays(self, unit):
+        # GH#30593
+        freq = offsets.CustomBusinessHour(start="15:00", holidays=["2020-11-26"])
+        result = date_range(start="2020-11-25 15:00", periods=4, freq=freq, unit=unit)
+        expected = DatetimeIndex(
+            [
+                "2020-11-25 15:00:00",
+                "2020-11-25 16:00:00",
+                "2020-11-27 15:00:00",
+                "2020-11-27 16:00:00",
+            ],
+            dtype=f"M8[{unit}]",
+            freq=freq,
+        )
+        tm.assert_index_equal(result, expected)
+
+    def test_date_range_businesshour(self, unit):
+        idx = DatetimeIndex(
+            [
+                "2014-07-04 09:00",
+                "2014-07-04 10:00",
+                "2014-07-04 11:00",
+                "2014-07-04 12:00",
+                "2014-07-04 13:00",
+                "2014-07-04 14:00",
+                "2014-07-04 15:00",
+                "2014-07-04 16:00",
+            ],
+            dtype=f"M8[{unit}]",
+            freq="bh",
+        )
+        rng = date_range("2014-07-04 09:00", "2014-07-04 16:00", freq="bh", unit=unit)
+        tm.assert_index_equal(idx, rng)
+
+        idx = DatetimeIndex(
+            ["2014-07-04 16:00", "2014-07-07 09:00"], dtype=f"M8[{unit}]", freq="bh"
+        )
+        rng = date_range("2014-07-04 16:00", "2014-07-07 09:00", freq="bh", unit=unit)
+        tm.assert_index_equal(idx, rng)
+
+        idx = DatetimeIndex(
+            [
+                "2014-07-04 09:00",
+                "2014-07-04 10:00",
+                "2014-07-04 11:00",
+                "2014-07-04 12:00",
+                "2014-07-04 13:00",
+                "2014-07-04 14:00",
+                "2014-07-04 15:00",
+                "2014-07-04 16:00",
+                "2014-07-07 09:00",
+                "2014-07-07 10:00",
+                "2014-07-07 11:00",
+                "2014-07-07 12:00",
+                "2014-07-07 13:00",
+                "2014-07-07 14:00",
+                "2014-07-07 15:00",
+                "2014-07-07 16:00",
+                "2014-07-08 09:00",
+                "2014-07-08 10:00",
+                "2014-07-08 11:00",
+                "2014-07-08 12:00",
+                "2014-07-08 13:00",
+                "2014-07-08 14:00",
+                "2014-07-08 15:00",
+                "2014-07-08 16:00",
+            ],
+            dtype=f"M8[{unit}]",
+            freq="bh",
+        )
+        rng = date_range("2014-07-04 09:00", "2014-07-08 16:00", freq="bh", unit=unit)
+        tm.assert_index_equal(idx, rng)
+
+    def test_date_range_business_hour2(self, unit):
+        idx1 = date_range(
+            start="2014-07-04 15:00", end="2014-07-08 10:00", freq="bh", unit=unit
+        )
+        idx2 = date_range(start="2014-07-04 15:00", periods=12, freq="bh", unit=unit)
+        idx3 = date_range(end="2014-07-08 10:00", periods=12, freq="bh", unit=unit)
+        expected = DatetimeIndex(
+            [
+                "2014-07-04 15:00",
+                "2014-07-04 16:00",
+                "2014-07-07 09:00",
+                "2014-07-07 10:00",
+                "2014-07-07 11:00",
+                "2014-07-07 12:00",
+                "2014-07-07 13:00",
+                "2014-07-07 14:00",
+                "2014-07-07 15:00",
+                "2014-07-07 16:00",
+                "2014-07-08 09:00",
+                "2014-07-08 10:00",
+            ],
+            dtype=f"M8[{unit}]",
+            freq="bh",
+        )
+        tm.assert_index_equal(idx1, expected)
+        tm.assert_index_equal(idx2, expected)
+        tm.assert_index_equal(idx3, expected)
+
+        idx4 = date_range(
+            start="2014-07-04 15:45", end="2014-07-08 10:45", freq="bh", unit=unit
+        )
+        idx5 = date_range(start="2014-07-04 15:45", periods=12, freq="bh", unit=unit)
+        idx6 = date_range(end="2014-07-08 10:45", periods=12, freq="bh", unit=unit)
+
+        expected2 = expected + Timedelta(minutes=45).as_unit(unit)
+        expected2.freq = "bh"
+        tm.assert_index_equal(idx4, expected2)
+        tm.assert_index_equal(idx5, expected2)
+        tm.assert_index_equal(idx6, expected2)
+
+    def test_date_range_business_hour_short(self, unit):
+        # GH#49835
+        idx4 = date_range(start="2014-07-01 10:00", freq="bh", periods=1, unit=unit)
+        expected4 = DatetimeIndex(["2014-07-01 10:00"], dtype=f"M8[{unit}]", freq="bh")
+        tm.assert_index_equal(idx4, expected4)
+
+    def test_date_range_year_start(self, unit):
+        # see GH#9313
+        rng = date_range("1/1/2013", "7/1/2017", freq="YS", unit=unit)
+        exp = DatetimeIndex(
+            ["2013-01-01", "2014-01-01", "2015-01-01", "2016-01-01", "2017-01-01"],
+            dtype=f"M8[{unit}]",
+            freq="YS",
+        )
+        tm.assert_index_equal(rng, exp)
+
+    def test_date_range_year_end(self, unit):
+        # see GH#9313
+        rng = date_range("1/1/2013", "7/1/2017", freq="YE", unit=unit)
+        exp = DatetimeIndex(
+            ["2013-12-31", "2014-12-31", "2015-12-31", "2016-12-31"],
+            dtype=f"M8[{unit}]",
+            freq="YE",
+        )
+        tm.assert_index_equal(rng, exp)
+
+    def test_date_range_negative_freq_year_end(self, unit):
+        # GH#11018
+        rng = date_range("2011-12-31", freq="-2YE", periods=3, unit=unit)
+        exp = DatetimeIndex(
+            ["2011-12-31", "2009-12-31", "2007-12-31"], dtype=f"M8[{unit}]", freq="-2YE"
+        )
+        tm.assert_index_equal(rng, exp)
+        assert rng.freq == "-2YE"
+
+    def test_date_range_business_year_end_year(self, unit):
+        # see GH#9313
+        rng = date_range("1/1/2013", "7/1/2017", freq="BYE", unit=unit)
+        exp = DatetimeIndex(
+            ["2013-12-31", "2014-12-31", "2015-12-31", "2016-12-30"],
+            dtype=f"M8[{unit}]",
+            freq="BYE",
+        )
+        tm.assert_index_equal(rng, exp)
+
+    def test_date_range_bms(self, unit):
+        # GH#1645
+        result = date_range("1/1/2000", periods=10, freq="BMS", unit=unit)
+
+        expected = DatetimeIndex(
+            [
+                "2000-01-03",
+                "2000-02-01",
+                "2000-03-01",
+                "2000-04-03",
+                "2000-05-01",
+                "2000-06-01",
+                "2000-07-03",
+                "2000-08-01",
+                "2000-09-01",
+                "2000-10-02",
+            ],
+            dtype=f"M8[{unit}]",
+            freq="BMS",
+        )
+        tm.assert_index_equal(result, expected)
+
+    def test_date_range_semi_month_begin(self, unit):
+        dates = [
+            datetime(2007, 12, 15),
+            datetime(2008, 1, 1),
+            datetime(2008, 1, 15),
+            datetime(2008, 2, 1),
+            datetime(2008, 2, 15),
+            datetime(2008, 3, 1),
+            datetime(2008, 3, 15),
+            datetime(2008, 4, 1),
+            datetime(2008, 4, 15),
+            datetime(2008, 5, 1),
+            datetime(2008, 5, 15),
+            datetime(2008, 6, 1),
+            datetime(2008, 6, 15),
+            datetime(2008, 7, 1),
+            datetime(2008, 7, 15),
+            datetime(2008, 8, 1),
+            datetime(2008, 8, 15),
+            datetime(2008, 9, 1),
+            datetime(2008, 9, 15),
+            datetime(2008, 10, 1),
+            datetime(2008, 10, 15),
+            datetime(2008, 11, 1),
+            datetime(2008, 11, 15),
+            datetime(2008, 12, 1),
+            datetime(2008, 12, 15),
+        ]
+        # ensure generating a range with DatetimeIndex gives same result
+        result = date_range(start=dates[0], end=dates[-1], freq="SMS", unit=unit)
+        exp = DatetimeIndex(dates, dtype=f"M8[{unit}]", freq="SMS")
+        tm.assert_index_equal(result, exp)
+
+    def test_date_range_semi_month_end(self, unit):
+        dates = [
+            datetime(2007, 12, 31),
+            datetime(2008, 1, 15),
+            datetime(2008, 1, 31),
+            datetime(2008, 2, 15),
+            datetime(2008, 2, 29),
+            datetime(2008, 3, 15),
+            datetime(2008, 3, 31),
+            datetime(2008, 4, 15),
+            datetime(2008, 4, 30),
+            datetime(2008, 5, 15),
+            datetime(2008, 5, 31),
+            datetime(2008, 6, 15),
+            datetime(2008, 6, 30),
+            datetime(2008, 7, 15),
+            datetime(2008, 7, 31),
+            datetime(2008, 8, 15),
+            datetime(2008, 8, 31),
+            datetime(2008, 9, 15),
+            datetime(2008, 9, 30),
+            datetime(2008, 10, 15),
+            datetime(2008, 10, 31),
+            datetime(2008, 11, 15),
+            datetime(2008, 11, 30),
+            datetime(2008, 12, 15),
+            datetime(2008, 12, 31),
+        ]
+        # ensure generating a range with DatetimeIndex gives same result
+        result = date_range(start=dates[0], end=dates[-1], freq="SME", unit=unit)
+        exp = DatetimeIndex(dates, dtype=f"M8[{unit}]", freq="SME")
+        tm.assert_index_equal(result, exp)
+
+    def test_date_range_week_of_month(self, unit):
+        # GH#20517
+        # Note the start here is not on_offset for this freq
+        result = date_range(start="20110101", periods=1, freq="WOM-1MON", unit=unit)
+        expected = DatetimeIndex(["2011-01-03"], dtype=f"M8[{unit}]", freq="WOM-1MON")
+        tm.assert_index_equal(result, expected)
+
+        result2 = date_range(start="20110101", periods=2, freq="WOM-1MON", unit=unit)
+        expected2 = DatetimeIndex(
+            ["2011-01-03", "2011-02-07"], dtype=f"M8[{unit}]", freq="WOM-1MON"
+        )
+        tm.assert_index_equal(result2, expected2)
+
+    def test_date_range_week_of_month2(self, unit):
+        # GH#5115, GH#5348
+        result = date_range("2013-1-1", periods=4, freq="WOM-1SAT", unit=unit)
+        expected = DatetimeIndex(
+            ["2013-01-05", "2013-02-02", "2013-03-02", "2013-04-06"],
+            dtype=f"M8[{unit}]",
+            freq="WOM-1SAT",
+        )
+        tm.assert_index_equal(result, expected)
+
+    def test_date_range_negative_freq_month_end(self, unit):
+        # GH#11018
+        rng = date_range("2011-01-31", freq="-2ME", periods=3, unit=unit)
+        exp = DatetimeIndex(
+            ["2011-01-31", "2010-11-30", "2010-09-30"], dtype=f"M8[{unit}]", freq="-2ME"
+        )
+        tm.assert_index_equal(rng, exp)
+        assert rng.freq == "-2ME"
+
+    def test_date_range_fy5253(self, unit):
+        freq = offsets.FY5253(startingMonth=1, weekday=3, variation="nearest")
+        dti = date_range(
+            start="2013-01-01",
+            periods=2,
+            freq=freq,
+            unit=unit,
+        )
+        expected = DatetimeIndex(
+            ["2013-01-31", "2014-01-30"], dtype=f"M8[{unit}]", freq=freq
+        )
+
+        tm.assert_index_equal(dti, expected)
+
+    @pytest.mark.parametrize(
+        "freqstr,offset",
+        [
+            ("QS", offsets.QuarterBegin(startingMonth=1)),
+            ("BQE", offsets.BQuarterEnd(startingMonth=12)),
+            ("W-SUN", offsets.Week(weekday=6)),
+        ],
+    )
+    def test_date_range_freqstr_matches_offset(self, freqstr, offset):
+        sdate = datetime(1999, 12, 25)
+        edate = datetime(2000, 1, 1)
+
+        idx1 = date_range(start=sdate, end=edate, freq=freqstr)
+        idx2 = date_range(start=sdate, end=edate, freq=offset)
+        assert len(idx1) == len(idx2)
+        assert idx1.freq == idx2.freq

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_datetime.py

@@ -0,0 +1,216 @@
+import datetime as dt
+from datetime import date
+import re
+
+import numpy as np
+import pytest
+
+from pandas.compat.numpy import np_long
+
+import pandas as pd
+from pandas import (
+    DataFrame,
+    DatetimeIndex,
+    Index,
+    Timestamp,
+    date_range,
+    offsets,
+)
+import pandas._testing as tm
+
+
+class TestDatetimeIndex:
+    def test_is_(self):
+        dti = date_range(start="1/1/2005", end="12/1/2005", freq="ME")
+        assert dti.is_(dti)
+        assert dti.is_(dti.view())
+        assert not dti.is_(dti.copy())
+
+    def test_time_overflow_for_32bit_machines(self):
+        # GH8943.  On some machines NumPy defaults to np.int32 (for example,
+        # 32-bit Linux machines).  In the function _generate_regular_range
+        # found in tseries/index.py, `periods` gets multiplied by `strides`
+        # (which has value 1e9) and since the max value for np.int32 is ~2e9,
+        # and since those machines won't promote np.int32 to np.int64, we get
+        # overflow.
+        periods = np_long(1000)
+
+        idx1 = date_range(start="2000", periods=periods, freq="s")
+        assert len(idx1) == periods
+
+        idx2 = date_range(end="2000", periods=periods, freq="s")
+        assert len(idx2) == periods
+
+    def test_nat(self):
+        assert DatetimeIndex([np.nan])[0] is pd.NaT
+
+    def test_week_of_month_frequency(self):
+        # GH 5348: "ValueError: Could not evaluate WOM-1SUN" shouldn't raise
+        d1 = date(2002, 9, 1)
+        d2 = date(2013, 10, 27)
+        d3 = date(2012, 9, 30)
+        idx1 = DatetimeIndex([d1, d2])
+        idx2 = DatetimeIndex([d3])
+        result_append = idx1.append(idx2)
+        expected = DatetimeIndex([d1, d2, d3])
+        tm.assert_index_equal(result_append, expected)
+        result_union = idx1.union(idx2)
+        expected = DatetimeIndex([d1, d3, d2])
+        tm.assert_index_equal(result_union, expected)
+
+    def test_append_nondatetimeindex(self):
+        rng = date_range("1/1/2000", periods=10)
+        idx = Index(["a", "b", "c", "d"])
+
+        result = rng.append(idx)
+        assert isinstance(result[0], Timestamp)
+
+    def test_misc_coverage(self):
+        rng = date_range("1/1/2000", periods=5)
+        result = rng.groupby(rng.day)
+        assert isinstance(next(iter(result.values()))[0], Timestamp)
+
+    # TODO: belongs in frame groupby tests?
+    def test_groupby_function_tuple_1677(self):
+        df = DataFrame(
+            np.random.default_rng(2).random(100),
+            index=date_range("1/1/2000", periods=100),
+        )
+        monthly_group = df.groupby(lambda x: (x.year, x.month))
+
+        result = monthly_group.mean()
+        assert isinstance(result.index[0], tuple)
+
+    def assert_index_parameters(self, index):
+        assert index.freq == "40960ns"
+        assert index.inferred_freq == "40960ns"
+
+    def test_ns_index(self):
+        nsamples = 400
+        ns = int(1e9 / 24414)
+        dtstart = np.datetime64("2012-09-20T00:00:00")
+
+        dt = dtstart + np.arange(nsamples) * np.timedelta64(ns, "ns")
+        freq = ns * offsets.Nano()
+        index = DatetimeIndex(dt, freq=freq, name="time")
+        self.assert_index_parameters(index)
+
+        new_index = date_range(start=index[0], end=index[-1], freq=index.freq)
+        self.assert_index_parameters(new_index)
+
+    def test_asarray_tz_naive(self):
+        # This shouldn't produce a warning.
+        idx = date_range("2000", periods=2)
+        # M8[ns] by default
+        result = np.asarray(idx)
+
+        expected = np.array(["2000-01-01", "2000-01-02"], dtype="M8[ns]")
+        tm.assert_numpy_array_equal(result, expected)
+
+        # optionally, object
+        result = np.asarray(idx, dtype=object)
+
+        expected = np.array([Timestamp("2000-01-01"), Timestamp("2000-01-02")])
+        tm.assert_numpy_array_equal(result, expected)
+
+    def test_asarray_tz_aware(self):
+        tz = "US/Central"
+        idx = date_range("2000", periods=2, tz=tz)
+        expected = np.array(["2000-01-01T06", "2000-01-02T06"], dtype="M8[ns]")
+        result = np.asarray(idx, dtype="datetime64[ns]")
+
+        tm.assert_numpy_array_equal(result, expected)
+
+        # Old behavior with no warning
+        result = np.asarray(idx, dtype="M8[ns]")
+
+        tm.assert_numpy_array_equal(result, expected)
+
+        # Future behavior with no warning
+        expected = np.array(
+            [Timestamp("2000-01-01", tz=tz), Timestamp("2000-01-02", tz=tz)]
+        )
+        result = np.asarray(idx, dtype=object)
+
+        tm.assert_numpy_array_equal(result, expected)
+
+    def test_CBH_deprecated(self):
+        msg = "'CBH' is deprecated and will be removed in a future version."
+
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            expected = date_range(
+                dt.datetime(2022, 12, 11), dt.datetime(2022, 12, 13), freq="CBH"
+            )
+        result = DatetimeIndex(
+            [
+                "2022-12-12 09:00:00",
+                "2022-12-12 10:00:00",
+                "2022-12-12 11:00:00",
+                "2022-12-12 12:00:00",
+                "2022-12-12 13:00:00",
+                "2022-12-12 14:00:00",
+                "2022-12-12 15:00:00",
+                "2022-12-12 16:00:00",
+            ],
+            dtype="datetime64[ns]",
+            freq="cbh",
+        )
+
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "freq_depr, expected_values, expected_freq",
+        [
+            (
+                "AS-AUG",
+                ["2021-08-01", "2022-08-01", "2023-08-01"],
+                "YS-AUG",
+            ),
+            (
+                "1BAS-MAY",
+                ["2021-05-03", "2022-05-02", "2023-05-01"],
+                "1BYS-MAY",
+            ),
+        ],
+    )
+    def test_AS_BAS_deprecated(self, freq_depr, expected_values, expected_freq):
+        # GH#55479
+        freq_msg = re.split("[0-9]*", freq_depr, maxsplit=1)[1]
+        msg = f"'{freq_msg}' is deprecated and will be removed in a future version."
+
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            expected = date_range(
+                dt.datetime(2020, 12, 1), dt.datetime(2023, 12, 1), freq=freq_depr
+            )
+        result = DatetimeIndex(
+            expected_values,
+            dtype="datetime64[ns]",
+            freq=expected_freq,
+        )
+
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "freq, expected_values, freq_depr",
+        [
+            ("2BYE-MAR", ["2016-03-31"], "2BA-MAR"),
+            ("2BYE-JUN", ["2016-06-30"], "2BY-JUN"),
+            ("2BME", ["2016-02-29", "2016-04-29", "2016-06-30"], "2BM"),
+            ("2BQE", ["2016-03-31"], "2BQ"),
+            ("1BQE-MAR", ["2016-03-31", "2016-06-30"], "1BQ-MAR"),
+        ],
+    )
+    def test_BM_BQ_BY_deprecated(self, freq, expected_values, freq_depr):
+        # GH#52064
+        msg = f"'{freq_depr[1:]}' is deprecated and will be removed "
+        f"in a future version, please use '{freq[1:]}' instead."
+
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            expected = date_range(start="2016-02-21", end="2016-08-21", freq=freq_depr)
+        result = DatetimeIndex(
+            data=expected_values,
+            dtype="datetime64[ns]",
+            freq=freq,
+        )
+
+        tm.assert_index_equal(result, expected)

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_formats.py

@@ -0,0 +1,356 @@
+from datetime import datetime
+
+import dateutil.tz
+import numpy as np
+import pytest
+import pytz
+
+import pandas as pd
+from pandas import (
+    DatetimeIndex,
+    NaT,
+    Series,
+)
+import pandas._testing as tm
+
+
+@pytest.fixture(params=["s", "ms", "us", "ns"])
+def unit(request):
+    return request.param
+
+
+def test_get_values_for_csv():
+    index = pd.date_range(freq="1D", periods=3, start="2017-01-01")
+
+    # First, with no arguments.
+    expected = np.array(["2017-01-01", "2017-01-02", "2017-01-03"], dtype=object)
+
+    result = index._get_values_for_csv()
+    tm.assert_numpy_array_equal(result, expected)
+
+    # No NaN values, so na_rep has no effect
+    result = index._get_values_for_csv(na_rep="pandas")
+    tm.assert_numpy_array_equal(result, expected)
+
+    # Make sure date formatting works
+    expected = np.array(["01-2017-01", "01-2017-02", "01-2017-03"], dtype=object)
+
+    result = index._get_values_for_csv(date_format="%m-%Y-%d")
+    tm.assert_numpy_array_equal(result, expected)
+
+    # NULL object handling should work
+    index = DatetimeIndex(["2017-01-01", NaT, "2017-01-03"])
+    expected = np.array(["2017-01-01", "NaT", "2017-01-03"], dtype=object)
+
+    result = index._get_values_for_csv(na_rep="NaT")
+    tm.assert_numpy_array_equal(result, expected)
+
+    expected = np.array(["2017-01-01", "pandas", "2017-01-03"], dtype=object)
+
+    result = index._get_values_for_csv(na_rep="pandas")
+    tm.assert_numpy_array_equal(result, expected)
+
+    result = index._get_values_for_csv(na_rep="NaT", date_format="%Y-%m-%d %H:%M:%S.%f")
+    expected = np.array(
+        ["2017-01-01 00:00:00.000000", "NaT", "2017-01-03 00:00:00.000000"],
+        dtype=object,
+    )
+    tm.assert_numpy_array_equal(result, expected)
+
+    # invalid format
+    result = index._get_values_for_csv(na_rep="NaT", date_format="foo")
+    expected = np.array(["foo", "NaT", "foo"], dtype=object)
+    tm.assert_numpy_array_equal(result, expected)
+
+
+class TestDatetimeIndexRendering:
+    @pytest.mark.parametrize("tzstr", ["US/Eastern", "dateutil/US/Eastern"])
+    def test_dti_with_timezone_repr(self, tzstr):
+        rng = pd.date_range("4/13/2010", "5/6/2010")
+
+        rng_eastern = rng.tz_localize(tzstr)
+
+        rng_repr = repr(rng_eastern)
+        assert "2010-04-13 00:00:00" in rng_repr
+
+    def test_dti_repr_dates(self):
+        text = str(pd.to_datetime([datetime(2013, 1, 1), datetime(2014, 1, 1)]))
+        assert "['2013-01-01'," in text
+        assert ", '2014-01-01']" in text
+
+    def test_dti_repr_mixed(self):
+        text = str(
+            pd.to_datetime(
+                [datetime(2013, 1, 1), datetime(2014, 1, 1, 12), datetime(2014, 1, 1)]
+            )
+        )
+        assert "'2013-01-01 00:00:00'," in text
+        assert "'2014-01-01 00:00:00']" in text
+
+    def test_dti_repr_short(self):
+        dr = pd.date_range(start="1/1/2012", periods=1)
+        repr(dr)
+
+        dr = pd.date_range(start="1/1/2012", periods=2)
+        repr(dr)
+
+        dr = pd.date_range(start="1/1/2012", periods=3)
+        repr(dr)
+
+    @pytest.mark.parametrize(
+        "dates, freq, expected_repr",
+        [
+            (
+                ["2012-01-01 00:00:00"],
+                "60min",
+                (
+                    "DatetimeIndex(['2012-01-01 00:00:00'], "
+                    "dtype='datetime64[ns]', freq='60min')"
+                ),
+            ),
+            (
+                ["2012-01-01 00:00:00", "2012-01-01 01:00:00"],
+                "60min",
+                "DatetimeIndex(['2012-01-01 00:00:00', '2012-01-01 01:00:00'], "
+                "dtype='datetime64[ns]', freq='60min')",
+            ),
+            (
+                ["2012-01-01"],
+                "24h",
+                "DatetimeIndex(['2012-01-01'], dtype='datetime64[ns]', freq='24h')",
+            ),
+        ],
+    )
+    def test_dti_repr_time_midnight(self, dates, freq, expected_repr, unit):
+        # GH53634
+        dti = DatetimeIndex(dates, freq).as_unit(unit)
+        actual_repr = repr(dti)
+        assert actual_repr == expected_repr.replace("[ns]", f"[{unit}]")
+
+    def test_dti_representation(self, unit):
+        idxs = []
+        idxs.append(DatetimeIndex([], freq="D"))
+        idxs.append(DatetimeIndex(["2011-01-01"], freq="D"))
+        idxs.append(DatetimeIndex(["2011-01-01", "2011-01-02"], freq="D"))
+        idxs.append(DatetimeIndex(["2011-01-01", "2011-01-02", "2011-01-03"], freq="D"))
+        idxs.append(
+            DatetimeIndex(
+                ["2011-01-01 09:00", "2011-01-01 10:00", "2011-01-01 11:00"],
+                freq="h",
+                tz="Asia/Tokyo",
+            )
+        )
+        idxs.append(
+            DatetimeIndex(
+                ["2011-01-01 09:00", "2011-01-01 10:00", NaT], tz="US/Eastern"
+            )
+        )
+        idxs.append(
+            DatetimeIndex(["2011-01-01 09:00", "2011-01-01 10:00", NaT], tz="UTC")
+        )
+
+        exp = []
+        exp.append("DatetimeIndex([], dtype='datetime64[ns]', freq='D')")
+        exp.append("DatetimeIndex(['2011-01-01'], dtype='datetime64[ns]', freq='D')")
+        exp.append(
+            "DatetimeIndex(['2011-01-01', '2011-01-02'], "
+            "dtype='datetime64[ns]', freq='D')"
+        )
+        exp.append(
+            "DatetimeIndex(['2011-01-01', '2011-01-02', '2011-01-03'], "
+            "dtype='datetime64[ns]', freq='D')"
+        )
+        exp.append(
+            "DatetimeIndex(['2011-01-01 09:00:00+09:00', "
+            "'2011-01-01 10:00:00+09:00', '2011-01-01 11:00:00+09:00']"
+            ", dtype='datetime64[ns, Asia/Tokyo]', freq='h')"
+        )
+        exp.append(
+            "DatetimeIndex(['2011-01-01 09:00:00-05:00', "
+            "'2011-01-01 10:00:00-05:00', 'NaT'], "
+            "dtype='datetime64[ns, US/Eastern]', freq=None)"
+        )
+        exp.append(
+            "DatetimeIndex(['2011-01-01 09:00:00+00:00', "
+            "'2011-01-01 10:00:00+00:00', 'NaT'], "
+            "dtype='datetime64[ns, UTC]', freq=None)"
+            ""
+        )
+
+        with pd.option_context("display.width", 300):
+            for index, expected in zip(idxs, exp):
+                index = index.as_unit(unit)
+                expected = expected.replace("[ns", f"[{unit}")
+                result = repr(index)
+                assert result == expected
+                result = str(index)
+                assert result == expected
+
+    # TODO: this is a Series.__repr__ test
+    def test_dti_representation_to_series(self, unit):
+        idx1 = DatetimeIndex([], freq="D")
+        idx2 = DatetimeIndex(["2011-01-01"], freq="D")
+        idx3 = DatetimeIndex(["2011-01-01", "2011-01-02"], freq="D")
+        idx4 = DatetimeIndex(["2011-01-01", "2011-01-02", "2011-01-03"], freq="D")
+        idx5 = DatetimeIndex(
+            ["2011-01-01 09:00", "2011-01-01 10:00", "2011-01-01 11:00"],
+            freq="h",
+            tz="Asia/Tokyo",
+        )
+        idx6 = DatetimeIndex(
+            ["2011-01-01 09:00", "2011-01-01 10:00", NaT], tz="US/Eastern"
+        )
+        idx7 = DatetimeIndex(["2011-01-01 09:00", "2011-01-02 10:15"])
+
+        exp1 = """Series([], dtype: datetime64[ns])"""
+
+        exp2 = "0   2011-01-01\ndtype: datetime64[ns]"
+
+        exp3 = "0   2011-01-01\n1   2011-01-02\ndtype: datetime64[ns]"
+
+        exp4 = (
+            "0   2011-01-01\n"
+            "1   2011-01-02\n"
+            "2   2011-01-03\n"
+            "dtype: datetime64[ns]"
+        )
+
+        exp5 = (
+            "0   2011-01-01 09:00:00+09:00\n"
+            "1   2011-01-01 10:00:00+09:00\n"
+            "2   2011-01-01 11:00:00+09:00\n"
+            "dtype: datetime64[ns, Asia/Tokyo]"
+        )
+
+        exp6 = (
+            "0   2011-01-01 09:00:00-05:00\n"
+            "1   2011-01-01 10:00:00-05:00\n"
+            "2                         NaT\n"
+            "dtype: datetime64[ns, US/Eastern]"
+        )
+
+        exp7 = (
+            "0   2011-01-01 09:00:00\n"
+            "1   2011-01-02 10:15:00\n"
+            "dtype: datetime64[ns]"
+        )
+
+        with pd.option_context("display.width", 300):
+            for idx, expected in zip(
+                [idx1, idx2, idx3, idx4, idx5, idx6, idx7],
+                [exp1, exp2, exp3, exp4, exp5, exp6, exp7],
+            ):
+                ser = Series(idx.as_unit(unit))
+                result = repr(ser)
+                assert result == expected.replace("[ns", f"[{unit}")
+
+    def test_dti_summary(self):
+        # GH#9116
+        idx1 = DatetimeIndex([], freq="D")
+        idx2 = DatetimeIndex(["2011-01-01"], freq="D")
+        idx3 = DatetimeIndex(["2011-01-01", "2011-01-02"], freq="D")
+        idx4 = DatetimeIndex(["2011-01-01", "2011-01-02", "2011-01-03"], freq="D")
+        idx5 = DatetimeIndex(
+            ["2011-01-01 09:00", "2011-01-01 10:00", "2011-01-01 11:00"],
+            freq="h",
+            tz="Asia/Tokyo",
+        )
+        idx6 = DatetimeIndex(
+            ["2011-01-01 09:00", "2011-01-01 10:00", NaT], tz="US/Eastern"
+        )
+
+        exp1 = "DatetimeIndex: 0 entries\nFreq: D"
+
+        exp2 = "DatetimeIndex: 1 entries, 2011-01-01 to 2011-01-01\nFreq: D"
+
+        exp3 = "DatetimeIndex: 2 entries, 2011-01-01 to 2011-01-02\nFreq: D"
+
+        exp4 = "DatetimeIndex: 3 entries, 2011-01-01 to 2011-01-03\nFreq: D"
+
+        exp5 = (
+            "DatetimeIndex: 3 entries, 2011-01-01 09:00:00+09:00 "
+            "to 2011-01-01 11:00:00+09:00\n"
+            "Freq: h"
+        )
+
+        exp6 = """DatetimeIndex: 3 entries, 2011-01-01 09:00:00-05:00 to NaT"""
+
+        for idx, expected in zip(
+            [idx1, idx2, idx3, idx4, idx5, idx6], [exp1, exp2, exp3, exp4, exp5, exp6]
+        ):
+            result = idx._summary()
+            assert result == expected
+
+    @pytest.mark.parametrize("tz", [None, pytz.utc, dateutil.tz.tzutc()])
+    @pytest.mark.parametrize("freq", ["B", "C"])
+    def test_dti_business_repr_etc_smoke(self, tz, freq):
+        # only really care that it works
+        dti = pd.bdate_range(
+            datetime(2009, 1, 1), datetime(2010, 1, 1), tz=tz, freq=freq
+        )
+        repr(dti)
+        dti._summary()
+        dti[2:2]._summary()
+
+
+class TestFormat:
+    def test_format(self):
+        # GH#35439
+        idx = pd.date_range("20130101", periods=5)
+        expected = [f"{x:%Y-%m-%d}" for x in idx]
+        msg = r"DatetimeIndex\.format is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            assert idx.format() == expected
+
+    def test_format_with_name_time_info(self):
+        # bug I fixed 12/20/2011
+        dates = pd.date_range("2011-01-01 04:00:00", periods=10, name="something")
+
+        msg = "DatetimeIndex.format is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            formatted = dates.format(name=True)
+        assert formatted[0] == "something"
+
+    def test_format_datetime_with_time(self):
+        dti = DatetimeIndex([datetime(2012, 2, 7), datetime(2012, 2, 7, 23)])
+
+        msg = "DatetimeIndex.format is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            result = dti.format()
+        expected = ["2012-02-07 00:00:00", "2012-02-07 23:00:00"]
+        assert len(result) == 2
+        assert result == expected
+
+    def test_format_datetime(self):
+        msg = "DatetimeIndex.format is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            formatted = pd.to_datetime([datetime(2003, 1, 1, 12), NaT]).format()
+        assert formatted[0] == "2003-01-01 12:00:00"
+        assert formatted[1] == "NaT"
+
+    def test_format_date(self):
+        msg = "DatetimeIndex.format is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            formatted = pd.to_datetime([datetime(2003, 1, 1), NaT]).format()
+        assert formatted[0] == "2003-01-01"
+        assert formatted[1] == "NaT"
+
+    def test_format_date_tz(self):
+        dti = pd.to_datetime([datetime(2013, 1, 1)], utc=True)
+        msg = "DatetimeIndex.format is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            formatted = dti.format()
+        assert formatted[0] == "2013-01-01 00:00:00+00:00"
+
+        dti = pd.to_datetime([datetime(2013, 1, 1), NaT], utc=True)
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            formatted = dti.format()
+        assert formatted[0] == "2013-01-01 00:00:00+00:00"
+
+    def test_format_date_explicit_date_format(self):
+        dti = pd.to_datetime([datetime(2003, 2, 1), NaT])
+        msg = "DatetimeIndex.format is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            formatted = dti.format(date_format="%m-%d-%Y", na_rep="UT")
+        assert formatted[0] == "02-01-2003"
+        assert formatted[1] == "UT"

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_freq_attr.py

@@ -0,0 +1,61 @@
+import pytest
+
+from pandas import (
+    DatetimeIndex,
+    date_range,
+)
+
+from pandas.tseries.offsets import (
+    BDay,
+    DateOffset,
+    Day,
+    Hour,
+)
+
+
+class TestFreq:
+    def test_freq_setter_errors(self):
+        # GH#20678
+        idx = DatetimeIndex(["20180101", "20180103", "20180105"])
+
+        # setting with an incompatible freq
+        msg = (
+            "Inferred frequency 2D from passed values does not conform to "
+            "passed frequency 5D"
+        )
+        with pytest.raises(ValueError, match=msg):
+            idx._data.freq = "5D"
+
+        # setting with non-freq string
+        with pytest.raises(ValueError, match="Invalid frequency"):
+            idx._data.freq = "foo"
+
+    @pytest.mark.parametrize("values", [["20180101", "20180103", "20180105"], []])
+    @pytest.mark.parametrize("freq", ["2D", Day(2), "2B", BDay(2), "48h", Hour(48)])
+    @pytest.mark.parametrize("tz", [None, "US/Eastern"])
+    def test_freq_setter(self, values, freq, tz):
+        # GH#20678
+        idx = DatetimeIndex(values, tz=tz)
+
+        # can set to an offset, converting from string if necessary
+        idx._data.freq = freq
+        assert idx.freq == freq
+        assert isinstance(idx.freq, DateOffset)
+
+        # can reset to None
+        idx._data.freq = None
+        assert idx.freq is None
+
+    def test_freq_view_safe(self):
+        # Setting the freq for one DatetimeIndex shouldn't alter the freq
+        #  for another that views the same data
+
+        dti = date_range("2016-01-01", periods=5)
+        dta = dti._data
+
+        dti2 = DatetimeIndex(dta)._with_freq(None)
+        assert dti2.freq is None
+
+        # Original was not altered
+        assert dti.freq == "D"
+        assert dta.freq == "D"

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_indexing.py

@@ -0,0 +1,717 @@
+from datetime import (
+    date,
+    datetime,
+    time,
+    timedelta,
+)
+
+import numpy as np
+import pytest
+
+from pandas._libs import index as libindex
+from pandas.compat.numpy import np_long
+
+import pandas as pd
+from pandas import (
+    DatetimeIndex,
+    Index,
+    Timestamp,
+    bdate_range,
+    date_range,
+    notna,
+)
+import pandas._testing as tm
+
+from pandas.tseries.frequencies import to_offset
+
+START, END = datetime(2009, 1, 1), datetime(2010, 1, 1)
+
+
+class TestGetItem:
+    def test_getitem_slice_keeps_name(self):
+        # GH4226
+        st = Timestamp("2013-07-01 00:00:00", tz="America/Los_Angeles")
+        et = Timestamp("2013-07-02 00:00:00", tz="America/Los_Angeles")
+        dr = date_range(st, et, freq="h", name="timebucket")
+        assert dr[1:].name == dr.name
+
+    @pytest.mark.parametrize("tz", [None, "Asia/Tokyo"])
+    def test_getitem(self, tz):
+        idx = date_range("2011-01-01", "2011-01-31", freq="D", tz=tz, name="idx")
+
+        result = idx[0]
+        assert result == Timestamp("2011-01-01", tz=idx.tz)
+
+        result = idx[0:5]
+        expected = date_range(
+            "2011-01-01", "2011-01-05", freq="D", tz=idx.tz, name="idx"
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq == expected.freq
+
+        result = idx[0:10:2]
+        expected = date_range(
+            "2011-01-01", "2011-01-09", freq="2D", tz=idx.tz, name="idx"
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq == expected.freq
+
+        result = idx[-20:-5:3]
+        expected = date_range(
+            "2011-01-12", "2011-01-24", freq="3D", tz=idx.tz, name="idx"
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq == expected.freq
+
+        result = idx[4::-1]
+        expected = DatetimeIndex(
+            ["2011-01-05", "2011-01-04", "2011-01-03", "2011-01-02", "2011-01-01"],
+            dtype=idx.dtype,
+            freq="-1D",
+            name="idx",
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq == expected.freq
+
+    @pytest.mark.parametrize("freq", ["B", "C"])
+    def test_dti_business_getitem(self, freq):
+        rng = bdate_range(START, END, freq=freq)
+        smaller = rng[:5]
+        exp = DatetimeIndex(rng.view(np.ndarray)[:5], freq=freq)
+        tm.assert_index_equal(smaller, exp)
+        assert smaller.freq == exp.freq
+        assert smaller.freq == rng.freq
+
+        sliced = rng[::5]
+        assert sliced.freq == to_offset(freq) * 5
+
+        fancy_indexed = rng[[4, 3, 2, 1, 0]]
+        assert len(fancy_indexed) == 5
+        assert isinstance(fancy_indexed, DatetimeIndex)
+        assert fancy_indexed.freq is None
+
+        # 32-bit vs. 64-bit platforms
+        assert rng[4] == rng[np_long(4)]
+
+    @pytest.mark.parametrize("freq", ["B", "C"])
+    def test_dti_business_getitem_matplotlib_hackaround(self, freq):
+        rng = bdate_range(START, END, freq=freq)
+        with pytest.raises(ValueError, match="Multi-dimensional indexing"):
+            # GH#30588 multi-dimensional indexing deprecated
+            rng[:, None]
+
+    def test_getitem_int_list(self):
+        dti = date_range(start="1/1/2005", end="12/1/2005", freq="ME")
+        dti2 = dti[[1, 3, 5]]
+
+        v1 = dti2[0]
+        v2 = dti2[1]
+        v3 = dti2[2]
+
+        assert v1 == Timestamp("2/28/2005")
+        assert v2 == Timestamp("4/30/2005")
+        assert v3 == Timestamp("6/30/2005")
+
+        # getitem with non-slice drops freq
+        assert dti2.freq is None
+
+
+class TestWhere:
+    def test_where_doesnt_retain_freq(self):
+        dti = date_range("20130101", periods=3, freq="D", name="idx")
+        cond = [True, True, False]
+        expected = DatetimeIndex([dti[0], dti[1], dti[0]], freq=None, name="idx")
+
+        result = dti.where(cond, dti[::-1])
+        tm.assert_index_equal(result, expected)
+
+    def test_where_other(self):
+        # other is ndarray or Index
+        i = date_range("20130101", periods=3, tz="US/Eastern")
+
+        for arr in [np.nan, pd.NaT]:
+            result = i.where(notna(i), other=arr)
+            expected = i
+            tm.assert_index_equal(result, expected)
+
+        i2 = i.copy()
+        i2 = Index([pd.NaT, pd.NaT] + i[2:].tolist())
+        result = i.where(notna(i2), i2)
+        tm.assert_index_equal(result, i2)
+
+        i2 = i.copy()
+        i2 = Index([pd.NaT, pd.NaT] + i[2:].tolist())
+        result = i.where(notna(i2), i2._values)
+        tm.assert_index_equal(result, i2)
+
+    def test_where_invalid_dtypes(self):
+        dti = date_range("20130101", periods=3, tz="US/Eastern")
+
+        tail = dti[2:].tolist()
+        i2 = Index([pd.NaT, pd.NaT] + tail)
+
+        mask = notna(i2)
+
+        # passing tz-naive ndarray to tzaware DTI
+        result = dti.where(mask, i2.values)
+        expected = Index([pd.NaT.asm8, pd.NaT.asm8] + tail, dtype=object)
+        tm.assert_index_equal(result, expected)
+
+        # passing tz-aware DTI to tznaive DTI
+        naive = dti.tz_localize(None)
+        result = naive.where(mask, i2)
+        expected = Index([i2[0], i2[1]] + naive[2:].tolist(), dtype=object)
+        tm.assert_index_equal(result, expected)
+
+        pi = i2.tz_localize(None).to_period("D")
+        result = dti.where(mask, pi)
+        expected = Index([pi[0], pi[1]] + tail, dtype=object)
+        tm.assert_index_equal(result, expected)
+
+        tda = i2.asi8.view("timedelta64[ns]")
+        result = dti.where(mask, tda)
+        expected = Index([tda[0], tda[1]] + tail, dtype=object)
+        assert isinstance(expected[0], np.timedelta64)
+        tm.assert_index_equal(result, expected)
+
+        result = dti.where(mask, i2.asi8)
+        expected = Index([pd.NaT._value, pd.NaT._value] + tail, dtype=object)
+        assert isinstance(expected[0], int)
+        tm.assert_index_equal(result, expected)
+
+        # non-matching scalar
+        td = pd.Timedelta(days=4)
+        result = dti.where(mask, td)
+        expected = Index([td, td] + tail, dtype=object)
+        assert expected[0] is td
+        tm.assert_index_equal(result, expected)
+
+    def test_where_mismatched_nat(self, tz_aware_fixture):
+        tz = tz_aware_fixture
+        dti = date_range("2013-01-01", periods=3, tz=tz)
+        cond = np.array([True, False, True])
+
+        tdnat = np.timedelta64("NaT", "ns")
+        expected = Index([dti[0], tdnat, dti[2]], dtype=object)
+        assert expected[1] is tdnat
+
+        result = dti.where(cond, tdnat)
+        tm.assert_index_equal(result, expected)
+
+    def test_where_tz(self):
+        i = date_range("20130101", periods=3, tz="US/Eastern")
+        result = i.where(notna(i))
+        expected = i
+        tm.assert_index_equal(result, expected)
+
+        i2 = i.copy()
+        i2 = Index([pd.NaT, pd.NaT] + i[2:].tolist())
+        result = i.where(notna(i2))
+        expected = i2
+        tm.assert_index_equal(result, expected)
+
+
+class TestTake:
+    @pytest.mark.parametrize("tzstr", ["US/Eastern", "dateutil/US/Eastern"])
+    def test_dti_take_dont_lose_meta(self, tzstr):
+        rng = date_range("1/1/2000", periods=20, tz=tzstr)
+
+        result = rng.take(range(5))
+        assert result.tz == rng.tz
+        assert result.freq == rng.freq
+
+    def test_take_nan_first_datetime(self):
+        index = DatetimeIndex([pd.NaT, Timestamp("20130101"), Timestamp("20130102")])
+        result = index.take([-1, 0, 1])
+        expected = DatetimeIndex([index[-1], index[0], index[1]])
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize("tz", [None, "Asia/Tokyo"])
+    def test_take(self, tz):
+        # GH#10295
+        idx = date_range("2011-01-01", "2011-01-31", freq="D", name="idx", tz=tz)
+
+        result = idx.take([0])
+        assert result == Timestamp("2011-01-01", tz=idx.tz)
+
+        result = idx.take([0, 1, 2])
+        expected = date_range(
+            "2011-01-01", "2011-01-03", freq="D", tz=idx.tz, name="idx"
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq == expected.freq
+
+        result = idx.take([0, 2, 4])
+        expected = date_range(
+            "2011-01-01", "2011-01-05", freq="2D", tz=idx.tz, name="idx"
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq == expected.freq
+
+        result = idx.take([7, 4, 1])
+        expected = date_range(
+            "2011-01-08", "2011-01-02", freq="-3D", tz=idx.tz, name="idx"
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq == expected.freq
+
+        result = idx.take([3, 2, 5])
+        expected = DatetimeIndex(
+            ["2011-01-04", "2011-01-03", "2011-01-06"],
+            dtype=idx.dtype,
+            freq=None,
+            name="idx",
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq is None
+
+        result = idx.take([-3, 2, 5])
+        expected = DatetimeIndex(
+            ["2011-01-29", "2011-01-03", "2011-01-06"],
+            dtype=idx.dtype,
+            freq=None,
+            name="idx",
+        )
+        tm.assert_index_equal(result, expected)
+        assert result.freq is None
+
+    def test_take_invalid_kwargs(self):
+        idx = date_range("2011-01-01", "2011-01-31", freq="D", name="idx")
+        indices = [1, 6, 5, 9, 10, 13, 15, 3]
+
+        msg = r"take\(\) got an unexpected keyword argument 'foo'"
+        with pytest.raises(TypeError, match=msg):
+            idx.take(indices, foo=2)
+
+        msg = "the 'out' parameter is not supported"
+        with pytest.raises(ValueError, match=msg):
+            idx.take(indices, out=indices)
+
+        msg = "the 'mode' parameter is not supported"
+        with pytest.raises(ValueError, match=msg):
+            idx.take(indices, mode="clip")
+
+    # TODO: This method came from test_datetime; de-dup with version above
+    @pytest.mark.parametrize("tz", [None, "US/Eastern", "Asia/Tokyo"])
+    def test_take2(self, tz):
+        dates = [
+            datetime(2010, 1, 1, 14),
+            datetime(2010, 1, 1, 15),
+            datetime(2010, 1, 1, 17),
+            datetime(2010, 1, 1, 21),
+        ]
+
+        idx = date_range(
+            start="2010-01-01 09:00",
+            end="2010-02-01 09:00",
+            freq="h",
+            tz=tz,
+            name="idx",
+        )
+        expected = DatetimeIndex(dates, freq=None, name="idx", dtype=idx.dtype)
+
+        taken1 = idx.take([5, 6, 8, 12])
+        taken2 = idx[[5, 6, 8, 12]]
+
+        for taken in [taken1, taken2]:
+            tm.assert_index_equal(taken, expected)
+            assert isinstance(taken, DatetimeIndex)
+            assert taken.freq is None
+            assert taken.tz == expected.tz
+            assert taken.name == expected.name
+
+    def test_take_fill_value(self):
+        # GH#12631
+        idx = DatetimeIndex(["2011-01-01", "2011-02-01", "2011-03-01"], name="xxx")
+        result = idx.take(np.array([1, 0, -1]))
+        expected = DatetimeIndex(["2011-02-01", "2011-01-01", "2011-03-01"], name="xxx")
+        tm.assert_index_equal(result, expected)
+
+        # fill_value
+        result = idx.take(np.array([1, 0, -1]), fill_value=True)
+        expected = DatetimeIndex(["2011-02-01", "2011-01-01", "NaT"], name="xxx")
+        tm.assert_index_equal(result, expected)
+
+        # allow_fill=False
+        result = idx.take(np.array([1, 0, -1]), allow_fill=False, fill_value=True)
+        expected = DatetimeIndex(["2011-02-01", "2011-01-01", "2011-03-01"], name="xxx")
+        tm.assert_index_equal(result, expected)
+
+        msg = (
+            "When allow_fill=True and fill_value is not None, "
+            "all indices must be >= -1"
+        )
+        with pytest.raises(ValueError, match=msg):
+            idx.take(np.array([1, 0, -2]), fill_value=True)
+        with pytest.raises(ValueError, match=msg):
+            idx.take(np.array([1, 0, -5]), fill_value=True)
+
+        msg = "out of bounds"
+        with pytest.raises(IndexError, match=msg):
+            idx.take(np.array([1, -5]))
+
+    def test_take_fill_value_with_timezone(self):
+        idx = DatetimeIndex(
+            ["2011-01-01", "2011-02-01", "2011-03-01"], name="xxx", tz="US/Eastern"
+        )
+        result = idx.take(np.array([1, 0, -1]))
+        expected = DatetimeIndex(
+            ["2011-02-01", "2011-01-01", "2011-03-01"], name="xxx", tz="US/Eastern"
+        )
+        tm.assert_index_equal(result, expected)
+
+        # fill_value
+        result = idx.take(np.array([1, 0, -1]), fill_value=True)
+        expected = DatetimeIndex(
+            ["2011-02-01", "2011-01-01", "NaT"], name="xxx", tz="US/Eastern"
+        )
+        tm.assert_index_equal(result, expected)
+
+        # allow_fill=False
+        result = idx.take(np.array([1, 0, -1]), allow_fill=False, fill_value=True)
+        expected = DatetimeIndex(
+            ["2011-02-01", "2011-01-01", "2011-03-01"], name="xxx", tz="US/Eastern"
+        )
+        tm.assert_index_equal(result, expected)
+
+        msg = (
+            "When allow_fill=True and fill_value is not None, "
+            "all indices must be >= -1"
+        )
+        with pytest.raises(ValueError, match=msg):
+            idx.take(np.array([1, 0, -2]), fill_value=True)
+        with pytest.raises(ValueError, match=msg):
+            idx.take(np.array([1, 0, -5]), fill_value=True)
+
+        msg = "out of bounds"
+        with pytest.raises(IndexError, match=msg):
+            idx.take(np.array([1, -5]))
+
+
+class TestGetLoc:
+    def test_get_loc_key_unit_mismatch(self):
+        idx = date_range("2000-01-01", periods=3)
+        key = idx[1].as_unit("ms")
+        loc = idx.get_loc(key)
+        assert loc == 1
+        assert key in idx
+
+    def test_get_loc_key_unit_mismatch_not_castable(self):
+        dta = date_range("2000-01-01", periods=3)._data.astype("M8[s]")
+        dti = DatetimeIndex(dta)
+        key = dta[0].as_unit("ns") + pd.Timedelta(1)
+
+        with pytest.raises(
+            KeyError, match=r"Timestamp\('2000-01-01 00:00:00.000000001'\)"
+        ):
+            dti.get_loc(key)
+
+        assert key not in dti
+
+    def test_get_loc_time_obj(self):
+        # time indexing
+        idx = date_range("2000-01-01", periods=24, freq="h")
+
+        result = idx.get_loc(time(12))
+        expected = np.array([12])
+        tm.assert_numpy_array_equal(result, expected, check_dtype=False)
+
+        result = idx.get_loc(time(12, 30))
+        expected = np.array([])
+        tm.assert_numpy_array_equal(result, expected, check_dtype=False)
+
+    @pytest.mark.parametrize("offset", [-10, 10])
+    def test_get_loc_time_obj2(self, monkeypatch, offset):
+        # GH#8667
+        size_cutoff = 50
+        n = size_cutoff + offset
+        key = time(15, 11, 30)
+        start = key.hour * 3600 + key.minute * 60 + key.second
+        step = 24 * 3600
+
+        with monkeypatch.context():
+            monkeypatch.setattr(libindex, "_SIZE_CUTOFF", size_cutoff)
+            idx = date_range("2014-11-26", periods=n, freq="s")
+            ts = pd.Series(np.random.default_rng(2).standard_normal(n), index=idx)
+            locs = np.arange(start, n, step, dtype=np.intp)
+
+            result = ts.index.get_loc(key)
+            tm.assert_numpy_array_equal(result, locs)
+            tm.assert_series_equal(ts[key], ts.iloc[locs])
+
+            left, right = ts.copy(), ts.copy()
+            left[key] *= -10
+            right.iloc[locs] *= -10
+            tm.assert_series_equal(left, right)
+
+    def test_get_loc_time_nat(self):
+        # GH#35114
+        # Case where key's total microseconds happens to match iNaT % 1e6 // 1000
+        tic = time(minute=12, second=43, microsecond=145224)
+        dti = DatetimeIndex([pd.NaT])
+
+        loc = dti.get_loc(tic)
+        expected = np.array([], dtype=np.intp)
+        tm.assert_numpy_array_equal(loc, expected)
+
+    def test_get_loc_nat(self):
+        # GH#20464
+        index = DatetimeIndex(["1/3/2000", "NaT"])
+        assert index.get_loc(pd.NaT) == 1
+
+        assert index.get_loc(None) == 1
+
+        assert index.get_loc(np.nan) == 1
+
+        assert index.get_loc(pd.NA) == 1
+
+        assert index.get_loc(np.datetime64("NaT")) == 1
+
+        with pytest.raises(KeyError, match="NaT"):
+            index.get_loc(np.timedelta64("NaT"))
+
+    @pytest.mark.parametrize("key", [pd.Timedelta(0), pd.Timedelta(1), timedelta(0)])
+    def test_get_loc_timedelta_invalid_key(self, key):
+        # GH#20464
+        dti = date_range("1970-01-01", periods=10)
+        msg = "Cannot index DatetimeIndex with [Tt]imedelta"
+        with pytest.raises(TypeError, match=msg):
+            dti.get_loc(key)
+
+    def test_get_loc_reasonable_key_error(self):
+        # GH#1062
+        index = DatetimeIndex(["1/3/2000"])
+        with pytest.raises(KeyError, match="2000"):
+            index.get_loc("1/1/2000")
+
+    def test_get_loc_year_str(self):
+        rng = date_range("1/1/2000", "1/1/2010")
+
+        result = rng.get_loc("2009")
+        expected = slice(3288, 3653)
+        assert result == expected
+
+
+class TestContains:
+    def test_dti_contains_with_duplicates(self):
+        d = datetime(2011, 12, 5, 20, 30)
+        ix = DatetimeIndex([d, d])
+        assert d in ix
+
+    @pytest.mark.parametrize(
+        "vals",
+        [
+            [0, 1, 0],
+            [0, 0, -1],
+            [0, -1, -1],
+            ["2015", "2015", "2016"],
+            ["2015", "2015", "2014"],
+        ],
+    )
+    def test_contains_nonunique(self, vals):
+        # GH#9512
+        idx = DatetimeIndex(vals)
+        assert idx[0] in idx
+
+
+class TestGetIndexer:
+    def test_get_indexer_date_objs(self):
+        rng = date_range("1/1/2000", periods=20)
+
+        result = rng.get_indexer(rng.map(lambda x: x.date()))
+        expected = rng.get_indexer(rng)
+        tm.assert_numpy_array_equal(result, expected)
+
+    def test_get_indexer(self):
+        idx = date_range("2000-01-01", periods=3)
+        exp = np.array([0, 1, 2], dtype=np.intp)
+        tm.assert_numpy_array_equal(idx.get_indexer(idx), exp)
+
+        target = idx[0] + pd.to_timedelta(["-1 hour", "12 hours", "1 day 1 hour"])
+        tm.assert_numpy_array_equal(
+            idx.get_indexer(target, "pad"), np.array([-1, 0, 1], dtype=np.intp)
+        )
+        tm.assert_numpy_array_equal(
+            idx.get_indexer(target, "backfill"), np.array([0, 1, 2], dtype=np.intp)
+        )
+        tm.assert_numpy_array_equal(
+            idx.get_indexer(target, "nearest"), np.array([0, 1, 1], dtype=np.intp)
+        )
+        tm.assert_numpy_array_equal(
+            idx.get_indexer(target, "nearest", tolerance=pd.Timedelta("1 hour")),
+            np.array([0, -1, 1], dtype=np.intp),
+        )
+        tol_raw = [
+            pd.Timedelta("1 hour"),
+            pd.Timedelta("1 hour"),
+            pd.Timedelta("1 hour").to_timedelta64(),
+        ]
+        tm.assert_numpy_array_equal(
+            idx.get_indexer(
+                target, "nearest", tolerance=[np.timedelta64(x) for x in tol_raw]
+            ),
+            np.array([0, -1, 1], dtype=np.intp),
+        )
+        tol_bad = [
+            pd.Timedelta("2 hour").to_timedelta64(),
+            pd.Timedelta("1 hour").to_timedelta64(),
+            "foo",
+        ]
+        msg = "Could not convert 'foo' to NumPy timedelta"
+        with pytest.raises(ValueError, match=msg):
+            idx.get_indexer(target, "nearest", tolerance=tol_bad)
+        with pytest.raises(ValueError, match="abbreviation w/o a number"):
+            idx.get_indexer(idx[[0]], method="nearest", tolerance="foo")
+
+    @pytest.mark.parametrize(
+        "target",
+        [
+            [date(2020, 1, 1), Timestamp("2020-01-02")],
+            [Timestamp("2020-01-01"), date(2020, 1, 2)],
+        ],
+    )
+    def test_get_indexer_mixed_dtypes(self, target):
+        # https://github.com/pandas-dev/pandas/issues/33741
+        values = DatetimeIndex([Timestamp("2020-01-01"), Timestamp("2020-01-02")])
+        result = values.get_indexer(target)
+        expected = np.array([0, 1], dtype=np.intp)
+        tm.assert_numpy_array_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "target, positions",
+        [
+            ([date(9999, 1, 1), Timestamp("2020-01-01")], [-1, 0]),
+            ([Timestamp("2020-01-01"), date(9999, 1, 1)], [0, -1]),
+            ([date(9999, 1, 1), date(9999, 1, 1)], [-1, -1]),
+        ],
+    )
+    def test_get_indexer_out_of_bounds_date(self, target, positions):
+        values = DatetimeIndex([Timestamp("2020-01-01"), Timestamp("2020-01-02")])
+
+        result = values.get_indexer(target)
+        expected = np.array(positions, dtype=np.intp)
+        tm.assert_numpy_array_equal(result, expected)
+
+    def test_get_indexer_pad_requires_monotonicity(self):
+        rng = date_range("1/1/2000", "3/1/2000", freq="B")
+
+        # neither monotonic increasing or decreasing
+        rng2 = rng[[1, 0, 2]]
+
+        msg = "index must be monotonic increasing or decreasing"
+        with pytest.raises(ValueError, match=msg):
+            rng2.get_indexer(rng, method="pad")
+
+
+class TestMaybeCastSliceBound:
+    def test_maybe_cast_slice_bounds_empty(self):
+        # GH#14354
+        empty_idx = date_range(freq="1h", periods=0, end="2015")
+
+        right = empty_idx._maybe_cast_slice_bound("2015-01-02", "right")
+        exp = Timestamp("2015-01-02 23:59:59.999999999")
+        assert right == exp
+
+        left = empty_idx._maybe_cast_slice_bound("2015-01-02", "left")
+        exp = Timestamp("2015-01-02 00:00:00")
+        assert left == exp
+
+    def test_maybe_cast_slice_duplicate_monotonic(self):
+        # https://github.com/pandas-dev/pandas/issues/16515
+        idx = DatetimeIndex(["2017", "2017"])
+        result = idx._maybe_cast_slice_bound("2017-01-01", "left")
+        expected = Timestamp("2017-01-01")
+        assert result == expected
+
+
+class TestGetSliceBounds:
+    @pytest.mark.parametrize("box", [date, datetime, Timestamp])
+    @pytest.mark.parametrize("side, expected", [("left", 4), ("right", 5)])
+    def test_get_slice_bounds_datetime_within(
+        self, box, side, expected, tz_aware_fixture
+    ):
+        # GH 35690
+        tz = tz_aware_fixture
+        index = bdate_range("2000-01-03", "2000-02-11").tz_localize(tz)
+        key = box(year=2000, month=1, day=7)
+
+        if tz is not None:
+            with pytest.raises(TypeError, match="Cannot compare tz-naive"):
+                # GH#36148 we require tzawareness-compat as of 2.0
+                index.get_slice_bound(key, side=side)
+        else:
+            result = index.get_slice_bound(key, side=side)
+            assert result == expected
+
+    @pytest.mark.parametrize("box", [datetime, Timestamp])
+    @pytest.mark.parametrize("side", ["left", "right"])
+    @pytest.mark.parametrize("year, expected", [(1999, 0), (2020, 30)])
+    def test_get_slice_bounds_datetime_outside(
+        self, box, side, year, expected, tz_aware_fixture
+    ):
+        # GH 35690
+        tz = tz_aware_fixture
+        index = bdate_range("2000-01-03", "2000-02-11").tz_localize(tz)
+        key = box(year=year, month=1, day=7)
+
+        if tz is not None:
+            with pytest.raises(TypeError, match="Cannot compare tz-naive"):
+                # GH#36148 we require tzawareness-compat as of 2.0
+                index.get_slice_bound(key, side=side)
+        else:
+            result = index.get_slice_bound(key, side=side)
+            assert result == expected
+
+    @pytest.mark.parametrize("box", [datetime, Timestamp])
+    def test_slice_datetime_locs(self, box, tz_aware_fixture):
+        # GH 34077
+        tz = tz_aware_fixture
+        index = DatetimeIndex(["2010-01-01", "2010-01-03"]).tz_localize(tz)
+        key = box(2010, 1, 1)
+
+        if tz is not None:
+            with pytest.raises(TypeError, match="Cannot compare tz-naive"):
+                # GH#36148 we require tzawareness-compat as of 2.0
+                index.slice_locs(key, box(2010, 1, 2))
+        else:
+            result = index.slice_locs(key, box(2010, 1, 2))
+            expected = (0, 1)
+            assert result == expected
+
+
+class TestIndexerBetweenTime:
+    def test_indexer_between_time(self):
+        # GH#11818
+        rng = date_range("1/1/2000", "1/5/2000", freq="5min")
+        msg = r"Cannot convert arg \[datetime\.datetime\(2010, 1, 2, 1, 0\)\] to a time"
+        with pytest.raises(ValueError, match=msg):
+            rng.indexer_between_time(datetime(2010, 1, 2, 1), datetime(2010, 1, 2, 5))
+
+    @pytest.mark.parametrize("unit", ["us", "ms", "s"])
+    def test_indexer_between_time_non_nano(self, unit):
+        # For simple cases like this, the non-nano indexer_between_time
+        #  should match the nano result
+
+        rng = date_range("1/1/2000", "1/5/2000", freq="5min")
+        arr_nano = rng._data._ndarray
+
+        arr = arr_nano.astype(f"M8[{unit}]")
+
+        dta = type(rng._data)._simple_new(arr, dtype=arr.dtype)
+        dti = DatetimeIndex(dta)
+        assert dti.dtype == arr.dtype
+
+        tic = time(1, 25)
+        toc = time(2, 29)
+
+        result = dti.indexer_between_time(tic, toc)
+        expected = rng.indexer_between_time(tic, toc)
+        tm.assert_numpy_array_equal(result, expected)
+
+        # case with non-zero micros in arguments
+        tic = time(1, 25, 0, 45678)
+        toc = time(2, 29, 0, 1234)
+
+        result = dti.indexer_between_time(tic, toc)
+        expected = rng.indexer_between_time(tic, toc)
+        tm.assert_numpy_array_equal(result, expected)

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_iter.py

@@ -0,0 +1,76 @@
+import dateutil.tz
+import numpy as np
+import pytest
+
+from pandas import (
+    DatetimeIndex,
+    date_range,
+    to_datetime,
+)
+from pandas.core.arrays import datetimes
+
+
+class TestDatetimeIndexIteration:
+    @pytest.mark.parametrize(
+        "tz", [None, "UTC", "US/Central", dateutil.tz.tzoffset(None, -28800)]
+    )
+    def test_iteration_preserves_nanoseconds(self, tz):
+        # GH#19603
+        index = DatetimeIndex(
+            ["2018-02-08 15:00:00.168456358", "2018-02-08 15:00:00.168456359"], tz=tz
+        )
+        for i, ts in enumerate(index):
+            assert ts == index[i]  # pylint: disable=unnecessary-list-index-lookup
+
+    def test_iter_readonly(self):
+        # GH#28055 ints_to_pydatetime with readonly array
+        arr = np.array([np.datetime64("2012-02-15T12:00:00.000000000")])
+        arr.setflags(write=False)
+        dti = to_datetime(arr)
+        list(dti)
+
+    def test_iteration_preserves_tz(self):
+        # see GH#8890
+        index = date_range("2012-01-01", periods=3, freq="h", tz="US/Eastern")
+
+        for i, ts in enumerate(index):
+            result = ts
+            expected = index[i]  # pylint: disable=unnecessary-list-index-lookup
+            assert result == expected
+
+    def test_iteration_preserves_tz2(self):
+        index = date_range(
+            "2012-01-01", periods=3, freq="h", tz=dateutil.tz.tzoffset(None, -28800)
+        )
+
+        for i, ts in enumerate(index):
+            result = ts
+            expected = index[i]  # pylint: disable=unnecessary-list-index-lookup
+            assert result._repr_base == expected._repr_base
+            assert result == expected
+
+    def test_iteration_preserves_tz3(self):
+        # GH#9100
+        index = DatetimeIndex(
+            ["2014-12-01 03:32:39.987000-08:00", "2014-12-01 04:12:34.987000-08:00"]
+        )
+        for i, ts in enumerate(index):
+            result = ts
+            expected = index[i]  # pylint: disable=unnecessary-list-index-lookup
+            assert result._repr_base == expected._repr_base
+            assert result == expected
+
+    @pytest.mark.parametrize("offset", [-5, -1, 0, 1])
+    def test_iteration_over_chunksize(self, offset, monkeypatch):
+        # GH#21012
+        chunksize = 5
+        index = date_range(
+            "2000-01-01 00:00:00", periods=chunksize - offset, freq="min"
+        )
+        num = 0
+        with monkeypatch.context() as m:
+            m.setattr(datetimes, "_ITER_CHUNKSIZE", chunksize)
+            for stamp in index:
+                assert index[num] == stamp
+                num += 1
+        assert num == len(index)

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_join.py

@@ -0,0 +1,149 @@
+from datetime import (
+    datetime,
+    timezone,
+)
+
+import numpy as np
+import pytest
+
+from pandas import (
+    DataFrame,
+    DatetimeIndex,
+    Index,
+    Timestamp,
+    date_range,
+    period_range,
+    to_datetime,
+)
+import pandas._testing as tm
+
+from pandas.tseries.offsets import (
+    BDay,
+    BMonthEnd,
+)
+
+
+class TestJoin:
+    def test_does_not_convert_mixed_integer(self):
+        df = DataFrame(np.ones((3, 2)), columns=date_range("2020-01-01", periods=2))
+        cols = df.columns.join(df.index, how="outer")
+        joined = cols.join(df.columns)
+        assert cols.dtype == np.dtype("O")
+        assert cols.dtype == joined.dtype
+        tm.assert_numpy_array_equal(cols.values, joined.values)
+
+    def test_join_self(self, join_type):
+        index = date_range("1/1/2000", periods=10)
+        joined = index.join(index, how=join_type)
+        assert index is joined
+
+    def test_join_with_period_index(self, join_type):
+        df = DataFrame(
+            np.ones((10, 2)),
+            index=date_range("2020-01-01", periods=10),
+            columns=period_range("2020-01-01", periods=2),
+        )
+        s = df.iloc[:5, 0]
+
+        expected = df.columns.astype("O").join(s.index, how=join_type)
+        result = df.columns.join(s.index, how=join_type)
+        tm.assert_index_equal(expected, result)
+
+    def test_join_object_index(self):
+        rng = date_range("1/1/2000", periods=10)
+        idx = Index(["a", "b", "c", "d"])
+
+        result = rng.join(idx, how="outer")
+        assert isinstance(result[0], Timestamp)
+
+    def test_join_utc_convert(self, join_type):
+        rng = date_range("1/1/2011", periods=100, freq="h", tz="utc")
+
+        left = rng.tz_convert("US/Eastern")
+        right = rng.tz_convert("Europe/Berlin")
+
+        result = left.join(left[:-5], how=join_type)
+        assert isinstance(result, DatetimeIndex)
+        assert result.tz == left.tz
+
+        result = left.join(right[:-5], how=join_type)
+        assert isinstance(result, DatetimeIndex)
+        assert result.tz is timezone.utc
+
+    def test_datetimeindex_union_join_empty(self, sort):
+        dti = date_range(start="1/1/2001", end="2/1/2001", freq="D")
+        empty = Index([])
+
+        result = dti.union(empty, sort=sort)
+        expected = dti.astype("O")
+        tm.assert_index_equal(result, expected)
+
+        result = dti.join(empty)
+        assert isinstance(result, DatetimeIndex)
+        tm.assert_index_equal(result, dti)
+
+    def test_join_nonunique(self):
+        idx1 = to_datetime(["2012-11-06 16:00:11.477563", "2012-11-06 16:00:11.477563"])
+        idx2 = to_datetime(["2012-11-06 15:11:09.006507", "2012-11-06 15:11:09.006507"])
+        rs = idx1.join(idx2, how="outer")
+        assert rs.is_monotonic_increasing
+
+    @pytest.mark.parametrize("freq", ["B", "C"])
+    def test_outer_join(self, freq):
+        # should just behave as union
+        start, end = datetime(2009, 1, 1), datetime(2010, 1, 1)
+        rng = date_range(start=start, end=end, freq=freq)
+
+        # overlapping
+        left = rng[:10]
+        right = rng[5:10]
+
+        the_join = left.join(right, how="outer")
+        assert isinstance(the_join, DatetimeIndex)
+
+        # non-overlapping, gap in middle
+        left = rng[:5]
+        right = rng[10:]
+
+        the_join = left.join(right, how="outer")
+        assert isinstance(the_join, DatetimeIndex)
+        assert the_join.freq is None
+
+        # non-overlapping, no gap
+        left = rng[:5]
+        right = rng[5:10]
+
+        the_join = left.join(right, how="outer")
+        assert isinstance(the_join, DatetimeIndex)
+
+        # overlapping, but different offset
+        other = date_range(start, end, freq=BMonthEnd())
+
+        the_join = rng.join(other, how="outer")
+        assert isinstance(the_join, DatetimeIndex)
+        assert the_join.freq is None
+
+    def test_naive_aware_conflicts(self):
+        start, end = datetime(2009, 1, 1), datetime(2010, 1, 1)
+        naive = date_range(start, end, freq=BDay(), tz=None)
+        aware = date_range(start, end, freq=BDay(), tz="Asia/Hong_Kong")
+
+        msg = "tz-naive.*tz-aware"
+        with pytest.raises(TypeError, match=msg):
+            naive.join(aware)
+
+        with pytest.raises(TypeError, match=msg):
+            aware.join(naive)
+
+    @pytest.mark.parametrize("tz", [None, "US/Pacific"])
+    def test_join_preserves_freq(self, tz):
+        # GH#32157
+        dti = date_range("2016-01-01", periods=10, tz=tz)
+        result = dti[:5].join(dti[5:], how="outer")
+        assert result.freq == dti.freq
+        tm.assert_index_equal(result, dti)
+
+        result = dti[:5].join(dti[6:], how="outer")
+        assert result.freq is None
+        expected = dti.delete(5)
+        tm.assert_index_equal(result, expected)

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_npfuncs.py

@@ -0,0 +1,13 @@
+import numpy as np
+
+from pandas import date_range
+import pandas._testing as tm
+
+
+class TestSplit:
+    def test_split_non_utc(self):
+        # GH#14042
+        indices = date_range("2016-01-01 00:00:00+0200", freq="s", periods=10)
+        result = np.split(indices, indices_or_sections=[])[0]
+        expected = indices._with_freq(None)
+        tm.assert_index_equal(result, expected)

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_ops.py

@@ -0,0 +1,56 @@
+from datetime import datetime
+
+import pytest
+
+from pandas import (
+    DatetimeIndex,
+    Index,
+    bdate_range,
+    date_range,
+)
+import pandas._testing as tm
+
+
+class TestDatetimeIndexOps:
+    def test_infer_freq(self, freq_sample):
+        # GH 11018
+        idx = date_range("2011-01-01 09:00:00", freq=freq_sample, periods=10)
+        result = DatetimeIndex(idx.asi8, freq="infer")
+        tm.assert_index_equal(idx, result)
+        assert result.freq == freq_sample
+
+
+@pytest.mark.parametrize("freq", ["B", "C"])
+class TestBusinessDatetimeIndex:
+    @pytest.fixture
+    def rng(self, freq):
+        START, END = datetime(2009, 1, 1), datetime(2010, 1, 1)
+        return bdate_range(START, END, freq=freq)
+
+    def test_comparison(self, rng):
+        d = rng[10]
+
+        comp = rng > d
+        assert comp[11]
+        assert not comp[9]
+
+    def test_copy(self, rng):
+        cp = rng.copy()
+        tm.assert_index_equal(cp, rng)
+
+    def test_identical(self, rng):
+        t1 = rng.copy()
+        t2 = rng.copy()
+        assert t1.identical(t2)
+
+        # name
+        t1 = t1.rename("foo")
+        assert t1.equals(t2)
+        assert not t1.identical(t2)
+        t2 = t2.rename("foo")
+        assert t1.identical(t2)
+
+        # freq
+        t2v = Index(t2.values)
+        assert t1.equals(t2v)
+        assert not t1.identical(t2v)

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_partial_slicing.py

@@ -0,0 +1,466 @@
+""" test partial slicing on Series/Frame """
+
+from datetime import datetime
+
+import numpy as np
+import pytest
+
+from pandas import (
+    DataFrame,
+    DatetimeIndex,
+    Index,
+    MultiIndex,
+    Series,
+    Timedelta,
+    Timestamp,
+    date_range,
+)
+import pandas._testing as tm
+
+
+class TestSlicing:
+    def test_string_index_series_name_converted(self):
+        # GH#1644
+        df = DataFrame(
+            np.random.default_rng(2).standard_normal((10, 4)),
+            index=date_range("1/1/2000", periods=10),
+        )
+
+        result = df.loc["1/3/2000"]
+        assert result.name == df.index[2]
+
+        result = df.T["1/3/2000"]
+        assert result.name == df.index[2]
+
+    def test_stringified_slice_with_tz(self):
+        # GH#2658
+        start = "2013-01-07"
+        idx = date_range(start=start, freq="1d", periods=10, tz="US/Eastern")
+        df = DataFrame(np.arange(10), index=idx)
+        df["2013-01-14 23:44:34.437768-05:00":]  # no exception here
+
+    def test_return_type_doesnt_depend_on_monotonicity(self):
+        # GH#24892 we get Series back regardless of whether our DTI is monotonic
+        dti = date_range(start="2015-5-13 23:59:00", freq="min", periods=3)
+        ser = Series(range(3), index=dti)
+
+        # non-monotonic index
+        ser2 = Series(range(3), index=[dti[1], dti[0], dti[2]])
+
+        # key with resolution strictly lower than "min"
+        key = "2015-5-14 00"
+
+        # monotonic increasing index
+        result = ser.loc[key]
+        expected = ser.iloc[1:]
+        tm.assert_series_equal(result, expected)
+
+        # monotonic decreasing index
+        result = ser.iloc[::-1].loc[key]
+        expected = ser.iloc[::-1][:-1]
+        tm.assert_series_equal(result, expected)
+
+        # non-monotonic index
+        result2 = ser2.loc[key]
+        expected2 = ser2.iloc[::2]
+        tm.assert_series_equal(result2, expected2)
+
+    def test_return_type_doesnt_depend_on_monotonicity_higher_reso(self):
+        # GH#24892 we get Series back regardless of whether our DTI is monotonic
+        dti = date_range(start="2015-5-13 23:59:00", freq="min", periods=3)
+        ser = Series(range(3), index=dti)
+
+        # non-monotonic index
+        ser2 = Series(range(3), index=[dti[1], dti[0], dti[2]])
+
+        # key with resolution strictly *higher) than "min"
+        key = "2015-5-14 00:00:00"
+
+        # monotonic increasing index
+        result = ser.loc[key]
+        assert result == 1
+
+        # monotonic decreasing index
+        result = ser.iloc[::-1].loc[key]
+        assert result == 1
+
+        # non-monotonic index
+        result2 = ser2.loc[key]
+        assert result2 == 0
+
+    def test_monotone_DTI_indexing_bug(self):
+        # GH 19362
+        # Testing accessing the first element in a monotonic descending
+        # partial string indexing.
+
+        df = DataFrame(list(range(5)))
+        date_list = [
+            "2018-01-02",
+            "2017-02-10",
+            "2016-03-10",
+            "2015-03-15",
+            "2014-03-16",
+        ]
+        date_index = DatetimeIndex(date_list)
+        df["date"] = date_index
+        expected = DataFrame({0: list(range(5)), "date": date_index})
+        tm.assert_frame_equal(df, expected)
+
+        # We get a slice because df.index's resolution is hourly and we
+        #  are slicing with a daily-resolution string.  If both were daily,
+        #  we would get a single item back
+        dti = date_range("20170101 01:00:00", periods=3)
+        df = DataFrame({"A": [1, 2, 3]}, index=dti[::-1])
+
+        expected = DataFrame({"A": 1}, index=dti[-1:][::-1])
+        result = df.loc["2017-01-03"]
+        tm.assert_frame_equal(result, expected)
+
+        result2 = df.iloc[::-1].loc["2017-01-03"]
+        expected2 = expected.iloc[::-1]
+        tm.assert_frame_equal(result2, expected2)
+
+    def test_slice_year(self):
+        dti = date_range(freq="B", start=datetime(2005, 1, 1), periods=500)
+
+        s = Series(np.arange(len(dti)), index=dti)
+        result = s["2005"]
+        expected = s[s.index.year == 2005]
+        tm.assert_series_equal(result, expected)
+
+        df = DataFrame(np.random.default_rng(2).random((len(dti), 5)), index=dti)
+        result = df.loc["2005"]
+        expected = df[df.index.year == 2005]
+        tm.assert_frame_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "partial_dtime",
+        [
+            "2019",
+            "2019Q4",
+            "Dec 2019",
+            "2019-12-31",
+            "2019-12-31 23",
+            "2019-12-31 23:59",
+        ],
+    )
+    def test_slice_end_of_period_resolution(self, partial_dtime):
+        # GH#31064
+        dti = date_range("2019-12-31 23:59:55.999999999", periods=10, freq="s")
+
+        ser = Series(range(10), index=dti)
+        result = ser[partial_dtime]
+        expected = ser.iloc[:5]
+        tm.assert_series_equal(result, expected)
+
+    def test_slice_quarter(self):
+        dti = date_range(freq="D", start=datetime(2000, 6, 1), periods=500)
+
+        s = Series(np.arange(len(dti)), index=dti)
+        assert len(s["2001Q1"]) == 90
+
+        df = DataFrame(np.random.default_rng(2).random((len(dti), 5)), index=dti)
+        assert len(df.loc["1Q01"]) == 90
+
+    def test_slice_month(self):
+        dti = date_range(freq="D", start=datetime(2005, 1, 1), periods=500)
+        s = Series(np.arange(len(dti)), index=dti)
+        assert len(s["2005-11"]) == 30
+
+        df = DataFrame(np.random.default_rng(2).random((len(dti), 5)), index=dti)
+        assert len(df.loc["2005-11"]) == 30
+
+        tm.assert_series_equal(s["2005-11"], s["11-2005"])
+
+    def test_partial_slice(self):
+        rng = date_range(freq="D", start=datetime(2005, 1, 1), periods=500)
+        s = Series(np.arange(len(rng)), index=rng)
+
+        result = s["2005-05":"2006-02"]
+        expected = s["20050501":"20060228"]
+        tm.assert_series_equal(result, expected)
+
+        result = s["2005-05":]
+        expected = s["20050501":]
+        tm.assert_series_equal(result, expected)
+
+        result = s[:"2006-02"]
+        expected = s[:"20060228"]
+        tm.assert_series_equal(result, expected)
+
+        result = s["2005-1-1"]
+        assert result == s.iloc[0]
+
+        with pytest.raises(KeyError, match=r"^'2004-12-31'$"):
+            s["2004-12-31"]
+
+    def test_partial_slice_daily(self):
+        rng = date_range(freq="h", start=datetime(2005, 1, 31), periods=500)
+        s = Series(np.arange(len(rng)), index=rng)
+
+        result = s["2005-1-31"]
+        tm.assert_series_equal(result, s.iloc[:24])
+
+        with pytest.raises(KeyError, match=r"^'2004-12-31 00'$"):
+            s["2004-12-31 00"]
+
+    def test_partial_slice_hourly(self):
+        rng = date_range(freq="min", start=datetime(2005, 1, 1, 20, 0, 0), periods=500)
+        s = Series(np.arange(len(rng)), index=rng)
+
+        result = s["2005-1-1"]
+        tm.assert_series_equal(result, s.iloc[: 60 * 4])
+
+        result = s["2005-1-1 20"]
+        tm.assert_series_equal(result, s.iloc[:60])
+
+        assert s["2005-1-1 20:00"] == s.iloc[0]
+        with pytest.raises(KeyError, match=r"^'2004-12-31 00:15'$"):
+            s["2004-12-31 00:15"]
+
+    def test_partial_slice_minutely(self):
+        rng = date_range(freq="s", start=datetime(2005, 1, 1, 23, 59, 0), periods=500)
+        s = Series(np.arange(len(rng)), index=rng)
+
+        result = s["2005-1-1 23:59"]
+        tm.assert_series_equal(result, s.iloc[:60])
+
+        result = s["2005-1-1"]
+        tm.assert_series_equal(result, s.iloc[:60])
+
+        assert s[Timestamp("2005-1-1 23:59:00")] == s.iloc[0]
+        with pytest.raises(KeyError, match=r"^'2004-12-31 00:00:00'$"):
+            s["2004-12-31 00:00:00"]
+
+    def test_partial_slice_second_precision(self):
+        rng = date_range(
+            start=datetime(2005, 1, 1, 0, 0, 59, microsecond=999990),
+            periods=20,
+            freq="us",
+        )
+        s = Series(np.arange(20), rng)
+
+        tm.assert_series_equal(s["2005-1-1 00:00"], s.iloc[:10])
+        tm.assert_series_equal(s["2005-1-1 00:00:59"], s.iloc[:10])
+
+        tm.assert_series_equal(s["2005-1-1 00:01"], s.iloc[10:])
+        tm.assert_series_equal(s["2005-1-1 00:01:00"], s.iloc[10:])
+
+        assert s[Timestamp("2005-1-1 00:00:59.999990")] == s.iloc[0]
+        with pytest.raises(KeyError, match="2005-1-1 00:00:00"):
+            s["2005-1-1 00:00:00"]
+
+    def test_partial_slicing_dataframe(self):
+        # GH14856
+        # Test various combinations of string slicing resolution vs.
+        # index resolution
+        # - If string resolution is less precise than index resolution,
+        # string is considered a slice
+        # - If string resolution is equal to or more precise than index
+        # resolution, string is considered an exact match
+        formats = [
+            "%Y",
+            "%Y-%m",
+            "%Y-%m-%d",
+            "%Y-%m-%d %H",
+            "%Y-%m-%d %H:%M",
+            "%Y-%m-%d %H:%M:%S",
+        ]
+        resolutions = ["year", "month", "day", "hour", "minute", "second"]
+        for rnum, resolution in enumerate(resolutions[2:], 2):
+            # we check only 'day', 'hour', 'minute' and 'second'
+            unit = Timedelta("1 " + resolution)
+            middate = datetime(2012, 1, 1, 0, 0, 0)
+            index = DatetimeIndex([middate - unit, middate, middate + unit])
+            values = [1, 2, 3]
+            df = DataFrame({"a": values}, index, dtype=np.int64)
+            assert df.index.resolution == resolution
+
+            # Timestamp with the same resolution as index
+            # Should be exact match for Series (return scalar)
+            # and raise KeyError for Frame
+            for timestamp, expected in zip(index, values):
+                ts_string = timestamp.strftime(formats[rnum])
+                # make ts_string as precise as index
+                result = df["a"][ts_string]
+                assert isinstance(result, np.int64)
+                assert result == expected
+                msg = rf"^'{ts_string}'$"
+                with pytest.raises(KeyError, match=msg):
+                    df[ts_string]
+
+            # Timestamp with resolution less precise than index
+            for fmt in formats[:rnum]:
+                for element, theslice in [[0, slice(None, 1)], [1, slice(1, None)]]:
+                    ts_string = index[element].strftime(fmt)
+
+                    # Series should return slice
+                    result = df["a"][ts_string]
+                    expected = df["a"][theslice]
+                    tm.assert_series_equal(result, expected)
+
+                    # pre-2.0 df[ts_string] was overloaded to interpret this
+                    #  as slicing along index
+                    with pytest.raises(KeyError, match=ts_string):
+                        df[ts_string]
+
+            # Timestamp with resolution more precise than index
+            # Compatible with existing key
+            # Should return scalar for Series
+            # and raise KeyError for Frame
+            for fmt in formats[rnum + 1 :]:
+                ts_string = index[1].strftime(fmt)
+                result = df["a"][ts_string]
+                assert isinstance(result, np.int64)
+                assert result == 2
+                msg = rf"^'{ts_string}'$"
+                with pytest.raises(KeyError, match=msg):
+                    df[ts_string]
+
+            # Not compatible with existing key
+            # Should raise KeyError
+            for fmt, res in list(zip(formats, resolutions))[rnum + 1 :]:
+                ts = index[1] + Timedelta("1 " + res)
+                ts_string = ts.strftime(fmt)
+                msg = rf"^'{ts_string}'$"
+                with pytest.raises(KeyError, match=msg):
+                    df["a"][ts_string]
+                with pytest.raises(KeyError, match=msg):
+                    df[ts_string]
+
+    def test_partial_slicing_with_multiindex(self):
+        # GH 4758
+        # partial string indexing with a multi-index buggy
+        df = DataFrame(
+            {
+                "ACCOUNT": ["ACCT1", "ACCT1", "ACCT1", "ACCT2"],
+                "TICKER": ["ABC", "MNP", "XYZ", "XYZ"],
+                "val": [1, 2, 3, 4],
+            },
+            index=date_range("2013-06-19 09:30:00", periods=4, freq="5min"),
+        )
+        df_multi = df.set_index(["ACCOUNT", "TICKER"], append=True)
+
+        expected = DataFrame(
+            [[1]], index=Index(["ABC"], name="TICKER"), columns=["val"]
+        )
+        result = df_multi.loc[("2013-06-19 09:30:00", "ACCT1")]
+        tm.assert_frame_equal(result, expected)
+
+        expected = df_multi.loc[
+            (Timestamp("2013-06-19 09:30:00", tz=None), "ACCT1", "ABC")
+        ]
+        result = df_multi.loc[("2013-06-19 09:30:00", "ACCT1", "ABC")]
+        tm.assert_series_equal(result, expected)
+
+        # partial string indexing on first level, scalar indexing on the other two
+        result = df_multi.loc[("2013-06-19", "ACCT1", "ABC")]
+        expected = df_multi.iloc[:1].droplevel([1, 2])
+        tm.assert_frame_equal(result, expected)
+
+    def test_partial_slicing_with_multiindex_series(self):
+        # GH 4294
+        # partial slice on a series mi
+        ser = Series(
+            range(250),
+            index=MultiIndex.from_product(
+                [date_range("2000-1-1", periods=50), range(5)]
+            ),
+        )
+
+        s2 = ser[:-1].copy()
+        expected = s2["2000-1-4"]
+        result = s2[Timestamp("2000-1-4")]
+        tm.assert_series_equal(result, expected)
+
+        result = ser[Timestamp("2000-1-4")]
+        expected = ser["2000-1-4"]
+        tm.assert_series_equal(result, expected)
+
+        df2 = DataFrame(ser)
+        expected = df2.xs("2000-1-4")
+        result = df2.loc[Timestamp("2000-1-4")]
+        tm.assert_frame_equal(result, expected)
+
+    def test_partial_slice_requires_monotonicity(self):
+        # Disallowed since 2.0 (GH 37819)
+        ser = Series(np.arange(10), date_range("2014-01-01", periods=10))
+
+        nonmonotonic = ser.iloc[[3, 5, 4]]
+        timestamp = Timestamp("2014-01-10")
+        with pytest.raises(
+            KeyError, match="Value based partial slicing on non-monotonic"
+        ):
+            nonmonotonic["2014-01-10":]
+
+        with pytest.raises(KeyError, match=r"Timestamp\('2014-01-10 00:00:00'\)"):
+            nonmonotonic[timestamp:]
+
+        with pytest.raises(
+            KeyError, match="Value based partial slicing on non-monotonic"
+        ):
+            nonmonotonic.loc["2014-01-10":]
+
+        with pytest.raises(KeyError, match=r"Timestamp\('2014-01-10 00:00:00'\)"):
+            nonmonotonic.loc[timestamp:]
+
+    def test_loc_datetime_length_one(self):
+        # GH16071
+        df = DataFrame(
+            columns=["1"],
+            index=date_range("2016-10-01T00:00:00", "2016-10-01T23:59:59"),
+        )
+        result = df.loc[datetime(2016, 10, 1) :]
+        tm.assert_frame_equal(result, df)
+
+        result = df.loc["2016-10-01T00:00:00":]
+        tm.assert_frame_equal(result, df)
+
+    @pytest.mark.parametrize(
+        "start",
+        [
+            "2018-12-02 21:50:00+00:00",
+            Timestamp("2018-12-02 21:50:00+00:00"),
+            Timestamp("2018-12-02 21:50:00+00:00").to_pydatetime(),
+        ],
+    )
+    @pytest.mark.parametrize(
+        "end",
+        [
+            "2018-12-02 21:52:00+00:00",
+            Timestamp("2018-12-02 21:52:00+00:00"),
+            Timestamp("2018-12-02 21:52:00+00:00").to_pydatetime(),
+        ],
+    )
+    def test_getitem_with_datestring_with_UTC_offset(self, start, end):
+        # GH 24076
+        idx = date_range(
+            start="2018-12-02 14:50:00-07:00",
+            end="2018-12-02 14:50:00-07:00",
+            freq="1min",
+        )
+        df = DataFrame(1, index=idx, columns=["A"])
+        result = df[start:end]
+        expected = df.iloc[0:3, :]
+        tm.assert_frame_equal(result, expected)
+
+        # GH 16785
+        start = str(start)
+        end = str(end)
+        with pytest.raises(ValueError, match="Both dates must"):
+            df[start : end[:-4] + "1:00"]
+
+        with pytest.raises(ValueError, match="The index must be timezone"):
+            df = df.tz_localize(None)
+            df[start:end]
+
+    def test_slice_reduce_to_series(self):
+        # GH 27516
+        df = DataFrame(
+            {"A": range(24)}, index=date_range("2000", periods=24, freq="ME")
+        )
+        expected = Series(
+            range(12), index=date_range("2000", periods=12, freq="ME"), name="A"
+        )
+        result = df.loc["2000", "A"]
+        tm.assert_series_equal(result, expected)

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_pickle.py

@@ -0,0 +1,45 @@
+import pytest
+
+from pandas import (
+    NaT,
+    date_range,
+    to_datetime,
+)
+import pandas._testing as tm
+
+
+class TestPickle:
+    def test_pickle(self):
+        # GH#4606
+        idx = to_datetime(["2013-01-01", NaT, "2014-01-06"])
+        idx_p = tm.round_trip_pickle(idx)
+        assert idx_p[0] == idx[0]
+        assert idx_p[1] is NaT
+        assert idx_p[2] == idx[2]
+
+    def test_pickle_dont_infer_freq(self):
+        # GH#11002
+        # don't infer freq
+        idx = date_range("1750-1-1", "2050-1-1", freq="7D")
+        idx_p = tm.round_trip_pickle(idx)
+        tm.assert_index_equal(idx, idx_p)
+
+    def test_pickle_after_set_freq(self):
+        dti = date_range("20130101", periods=3, tz="US/Eastern", name="foo")
+        dti = dti._with_freq(None)
+
+        res = tm.round_trip_pickle(dti)
+        tm.assert_index_equal(res, dti)
+
+    def test_roundtrip_pickle_with_tz(self):
+        # GH#8367
+        # round-trip of timezone
+        index = date_range("20130101", periods=3, tz="US/Eastern", name="foo")
+        unpickled = tm.round_trip_pickle(index)
+        tm.assert_index_equal(index, unpickled)
+
+    @pytest.mark.parametrize("freq", ["B", "C"])
+    def test_pickle_unpickle(self, freq):
+        rng = date_range("2009-01-01", "2010-01-01", freq=freq)
+        unpickled = tm.round_trip_pickle(rng)
+        assert unpickled.freq == freq

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_reindex.py

@@ -0,0 +1,56 @@
+from datetime import timedelta
+
+import numpy as np
+
+from pandas import (
+    DatetimeIndex,
+    date_range,
+)
+import pandas._testing as tm
+
+
+class TestDatetimeIndexReindex:
+    def test_reindex_preserves_tz_if_target_is_empty_list_or_array(self):
+        # GH#7774
+        index = date_range("2013-01-01", periods=3, tz="US/Eastern")
+        assert str(index.reindex([])[0].tz) == "US/Eastern"
+        assert str(index.reindex(np.array([]))[0].tz) == "US/Eastern"
+
+    def test_reindex_with_same_tz_nearest(self):
+        # GH#32740
+        rng_a = date_range("2010-01-01", "2010-01-02", periods=24, tz="utc")
+        rng_b = date_range("2010-01-01", "2010-01-02", periods=23, tz="utc")
+        result1, result2 = rng_a.reindex(
+            rng_b, method="nearest", tolerance=timedelta(seconds=20)
+        )
+        expected_list1 = [
+            "2010-01-01 00:00:00",
+            "2010-01-01 01:05:27.272727272",
+            "2010-01-01 02:10:54.545454545",
+            "2010-01-01 03:16:21.818181818",
+            "2010-01-01 04:21:49.090909090",
+            "2010-01-01 05:27:16.363636363",
+            "2010-01-01 06:32:43.636363636",
+            "2010-01-01 07:38:10.909090909",
+            "2010-01-01 08:43:38.181818181",
+            "2010-01-01 09:49:05.454545454",
+            "2010-01-01 10:54:32.727272727",
+            "2010-01-01 12:00:00",
+            "2010-01-01 13:05:27.272727272",
+            "2010-01-01 14:10:54.545454545",
+            "2010-01-01 15:16:21.818181818",
+            "2010-01-01 16:21:49.090909090",
+            "2010-01-01 17:27:16.363636363",
+            "2010-01-01 18:32:43.636363636",
+            "2010-01-01 19:38:10.909090909",
+            "2010-01-01 20:43:38.181818181",
+            "2010-01-01 21:49:05.454545454",
+            "2010-01-01 22:54:32.727272727",
+            "2010-01-02 00:00:00",
+        ]
+        expected1 = DatetimeIndex(
+            expected_list1, dtype="datetime64[ns, UTC]", freq=None
+        )
+        expected2 = np.array([0] + [-1] * 21 + [23], dtype=np.dtype("intp"))
+        tm.assert_index_equal(result1, expected1)
+        tm.assert_numpy_array_equal(result2, expected2)

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_scalar_compat.py

@@ -0,0 +1,329 @@
+"""
+Tests for DatetimeIndex methods behaving like their Timestamp counterparts
+"""
+
+import calendar
+from datetime import (
+    date,
+    datetime,
+    time,
+)
+import locale
+import unicodedata
+
+import numpy as np
+import pytest
+
+from pandas._libs.tslibs import timezones
+
+from pandas import (
+    DatetimeIndex,
+    Index,
+    NaT,
+    Timestamp,
+    date_range,
+    offsets,
+)
+import pandas._testing as tm
+from pandas.core.arrays import DatetimeArray
+
+
+class TestDatetimeIndexOps:
+    def test_dti_no_millisecond_field(self):
+        msg = "type object 'DatetimeIndex' has no attribute 'millisecond'"
+        with pytest.raises(AttributeError, match=msg):
+            DatetimeIndex.millisecond
+
+        msg = "'DatetimeIndex' object has no attribute 'millisecond'"
+        with pytest.raises(AttributeError, match=msg):
+            DatetimeIndex([]).millisecond
+
+    def test_dti_time(self):
+        rng = date_range("1/1/2000", freq="12min", periods=10)
+        result = Index(rng).time
+        expected = [t.time() for t in rng]
+        assert (result == expected).all()
+
+    def test_dti_date(self):
+        rng = date_range("1/1/2000", freq="12h", periods=10)
+        result = Index(rng).date
+        expected = [t.date() for t in rng]
+        assert (result == expected).all()
+
+    @pytest.mark.parametrize(
+        "dtype",
+        [None, "datetime64[ns, CET]", "datetime64[ns, EST]", "datetime64[ns, UTC]"],
+    )
+    def test_dti_date2(self, dtype):
+        # Regression test for GH#21230
+        expected = np.array([date(2018, 6, 4), NaT])
+
+        index = DatetimeIndex(["2018-06-04 10:00:00", NaT], dtype=dtype)
+        result = index.date
+
+        tm.assert_numpy_array_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "dtype",
+        [None, "datetime64[ns, CET]", "datetime64[ns, EST]", "datetime64[ns, UTC]"],
+    )
+    def test_dti_time2(self, dtype):
+        # Regression test for GH#21267
+        expected = np.array([time(10, 20, 30), NaT])
+
+        index = DatetimeIndex(["2018-06-04 10:20:30", NaT], dtype=dtype)
+        result = index.time
+
+        tm.assert_numpy_array_equal(result, expected)
+
+    def test_dti_timetz(self, tz_naive_fixture):
+        # GH#21358
+        tz = timezones.maybe_get_tz(tz_naive_fixture)
+
+        expected = np.array([time(10, 20, 30, tzinfo=tz), NaT])
+
+        index = DatetimeIndex(["2018-06-04 10:20:30", NaT], tz=tz)
+        result = index.timetz
+
+        tm.assert_numpy_array_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "field",
+        [
+            "dayofweek",
+            "day_of_week",
+            "dayofyear",
+            "day_of_year",
+            "quarter",
+            "days_in_month",
+            "is_month_start",
+            "is_month_end",
+            "is_quarter_start",
+            "is_quarter_end",
+            "is_year_start",
+            "is_year_end",
+        ],
+    )
+    def test_dti_timestamp_fields(self, field):
+        # extra fields from DatetimeIndex like quarter and week
+        idx = date_range("2020-01-01", periods=10)
+        expected = getattr(idx, field)[-1]
+
+        result = getattr(Timestamp(idx[-1]), field)
+        assert result == expected
+
+    def test_dti_nanosecond(self):
+        dti = DatetimeIndex(np.arange(10))
+        expected = Index(np.arange(10, dtype=np.int32))
+
+        tm.assert_index_equal(dti.nanosecond, expected)
+
+    @pytest.mark.parametrize("prefix", ["", "dateutil/"])
+    def test_dti_hour_tzaware(self, prefix):
+        strdates = ["1/1/2012", "3/1/2012", "4/1/2012"]
+        rng = DatetimeIndex(strdates, tz=prefix + "US/Eastern")
+        assert (rng.hour == 0).all()
+
+        # a more unusual time zone, GH#1946
+        dr = date_range(
+            "2011-10-02 00:00", freq="h", periods=10, tz=prefix + "America/Atikokan"
+        )
+
+        expected = Index(np.arange(10, dtype=np.int32))
+        tm.assert_index_equal(dr.hour, expected)
+
+    # GH#12806
+    # error: Unsupported operand types for + ("List[None]" and "List[str]")
+    @pytest.mark.parametrize(
+        "time_locale", [None] + tm.get_locales()  # type: ignore[operator]
+    )
+    def test_day_name_month_name(self, time_locale):
+        # Test Monday -> Sunday and January -> December, in that sequence
+        if time_locale is None:
+            # If the time_locale is None, day-name and month_name should
+            # return the english attributes
+            expected_days = [
+                "Monday",
+                "Tuesday",
+                "Wednesday",
+                "Thursday",
+                "Friday",
+                "Saturday",
+                "Sunday",
+            ]
+            expected_months = [
+                "January",
+                "February",
+                "March",
+                "April",
+                "May",
+                "June",
+                "July",
+                "August",
+                "September",
+                "October",
+                "November",
+                "December",
+            ]
+        else:
+            with tm.set_locale(time_locale, locale.LC_TIME):
+                expected_days = calendar.day_name[:]
+                expected_months = calendar.month_name[1:]
+
+        # GH#11128
+        dti = date_range(freq="D", start=datetime(1998, 1, 1), periods=365)
+        english_days = [
+            "Monday",
+            "Tuesday",
+            "Wednesday",
+            "Thursday",
+            "Friday",
+            "Saturday",
+            "Sunday",
+        ]
+        for day, name, eng_name in zip(range(4, 11), expected_days, english_days):
+            name = name.capitalize()
+            assert dti.day_name(locale=time_locale)[day] == name
+            assert dti.day_name(locale=None)[day] == eng_name
+            ts = Timestamp(datetime(2016, 4, day))
+            assert ts.day_name(locale=time_locale) == name
+        dti = dti.append(DatetimeIndex([NaT]))
+        assert np.isnan(dti.day_name(locale=time_locale)[-1])
+        ts = Timestamp(NaT)
+        assert np.isnan(ts.day_name(locale=time_locale))
+
+        # GH#12805
+        dti = date_range(freq="ME", start="2012", end="2013")
+        result = dti.month_name(locale=time_locale)
+        expected = Index([month.capitalize() for month in expected_months])
+
+        # work around different normalization schemes GH#22342
+        result = result.str.normalize("NFD")
+        expected = expected.str.normalize("NFD")
+
+        tm.assert_index_equal(result, expected)
+
+        for item, expected in zip(dti, expected_months):
+            result = item.month_name(locale=time_locale)
+            expected = expected.capitalize()
+
+            result = unicodedata.normalize("NFD", result)
+            expected = unicodedata.normalize("NFD", result)
+
+            assert result == expected
+        dti = dti.append(DatetimeIndex([NaT]))
+        assert np.isnan(dti.month_name(locale=time_locale)[-1])
+
+    def test_dti_week(self):
+        # GH#6538: Check that DatetimeIndex and its TimeStamp elements
+        # return the same weekofyear accessor close to new year w/ tz
+        dates = ["2013/12/29", "2013/12/30", "2013/12/31"]
+        dates = DatetimeIndex(dates, tz="Europe/Brussels")
+        expected = [52, 1, 1]
+        assert dates.isocalendar().week.tolist() == expected
+        assert [d.weekofyear for d in dates] == expected
+
+    @pytest.mark.parametrize("tz", [None, "US/Eastern"])
+    def test_dti_fields(self, tz):
+        # GH#13303
+        dti = date_range(freq="D", start=datetime(1998, 1, 1), periods=365, tz=tz)
+        assert dti.year[0] == 1998
+        assert dti.month[0] == 1
+        assert dti.day[0] == 1
+        assert dti.hour[0] == 0
+        assert dti.minute[0] == 0
+        assert dti.second[0] == 0
+        assert dti.microsecond[0] == 0
+        assert dti.dayofweek[0] == 3
+
+        assert dti.dayofyear[0] == 1
+        assert dti.dayofyear[120] == 121
+
+        assert dti.isocalendar().week.iloc[0] == 1
+        assert dti.isocalendar().week.iloc[120] == 18
+
+        assert dti.quarter[0] == 1
+        assert dti.quarter[120] == 2
+
+        assert dti.days_in_month[0] == 31
+        assert dti.days_in_month[90] == 30
+
+        assert dti.is_month_start[0]
+        assert not dti.is_month_start[1]
+        assert dti.is_month_start[31]
+        assert dti.is_quarter_start[0]
+        assert dti.is_quarter_start[90]
+        assert dti.is_year_start[0]
+        assert not dti.is_year_start[364]
+        assert not dti.is_month_end[0]
+        assert dti.is_month_end[30]
+        assert not dti.is_month_end[31]
+        assert dti.is_month_end[364]
+        assert not dti.is_quarter_end[0]
+        assert not dti.is_quarter_end[30]
+        assert dti.is_quarter_end[89]
+        assert dti.is_quarter_end[364]
+        assert not dti.is_year_end[0]
+        assert dti.is_year_end[364]
+
+        assert len(dti.year) == 365
+        assert len(dti.month) == 365
+        assert len(dti.day) == 365
+        assert len(dti.hour) == 365
+        assert len(dti.minute) == 365
+        assert len(dti.second) == 365
+        assert len(dti.microsecond) == 365
+        assert len(dti.dayofweek) == 365
+        assert len(dti.dayofyear) == 365
+        assert len(dti.isocalendar()) == 365
+        assert len(dti.quarter) == 365
+        assert len(dti.is_month_start) == 365
+        assert len(dti.is_month_end) == 365
+        assert len(dti.is_quarter_start) == 365
+        assert len(dti.is_quarter_end) == 365
+        assert len(dti.is_year_start) == 365
+        assert len(dti.is_year_end) == 365
+
+        dti.name = "name"
+
+        # non boolean accessors -> return Index
+        for accessor in DatetimeArray._field_ops:
+            res = getattr(dti, accessor)
+            assert len(res) == 365
+            assert isinstance(res, Index)
+            assert res.name == "name"
+
+        # boolean accessors -> return array
+        for accessor in DatetimeArray._bool_ops:
+            res = getattr(dti, accessor)
+            assert len(res) == 365
+            assert isinstance(res, np.ndarray)
+
+        # test boolean indexing
+        res = dti[dti.is_quarter_start]
+        exp = dti[[0, 90, 181, 273]]
+        tm.assert_index_equal(res, exp)
+        res = dti[dti.is_leap_year]
+        exp = DatetimeIndex([], freq="D", tz=dti.tz, name="name").as_unit("ns")
+        tm.assert_index_equal(res, exp)
+
+    def test_dti_is_year_quarter_start(self):
+        dti = date_range(freq="BQE-FEB", start=datetime(1998, 1, 1), periods=4)
+
+        assert sum(dti.is_quarter_start) == 0
+        assert sum(dti.is_quarter_end) == 4
+        assert sum(dti.is_year_start) == 0
+        assert sum(dti.is_year_end) == 1
+
+    def test_dti_is_month_start(self):
+        dti = DatetimeIndex(["2000-01-01", "2000-01-02", "2000-01-03"])
+
+        assert dti.is_month_start[0] == 1
+
+    def test_dti_is_month_start_custom(self):
+        # Ensure is_start/end accessors throw ValueError for CustomBusinessDay,
+        bday_egypt = offsets.CustomBusinessDay(weekmask="Sun Mon Tue Wed Thu")
+        dti = date_range(datetime(2013, 4, 30), periods=5, freq=bday_egypt)
+        msg = "Custom business days is not supported by is_month_start"
+        with pytest.raises(ValueError, match=msg):
+            dti.is_month_start

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_setops.py

@@ -0,0 +1,666 @@
+from datetime import (
+    datetime,
+    timezone,
+)
+
+import numpy as np
+import pytest
+import pytz
+
+import pandas.util._test_decorators as td
+
+import pandas as pd
+from pandas import (
+    DataFrame,
+    DatetimeIndex,
+    Index,
+    Series,
+    Timestamp,
+    bdate_range,
+    date_range,
+)
+import pandas._testing as tm
+
+from pandas.tseries.offsets import (
+    BMonthEnd,
+    Minute,
+    MonthEnd,
+)
+
+START, END = datetime(2009, 1, 1), datetime(2010, 1, 1)
+
+
+class TestDatetimeIndexSetOps:
+    tz = [
+        None,
+        "UTC",
+        "Asia/Tokyo",
+        "US/Eastern",
+        "dateutil/Asia/Singapore",
+        "dateutil/US/Pacific",
+    ]
+
+    # TODO: moved from test_datetimelike; dedup with version below
+    def test_union2(self, sort):
+        everything = date_range("2020-01-01", periods=10)
+        first = everything[:5]
+        second = everything[5:]
+        union = first.union(second, sort=sort)
+        tm.assert_index_equal(union, everything)
+
+    @pytest.mark.parametrize("box", [np.array, Series, list])
+    def test_union3(self, sort, box):
+        everything = date_range("2020-01-01", periods=10)
+        first = everything[:5]
+        second = everything[5:]
+
+        # GH 10149 support listlike inputs other than Index objects
+        expected = first.union(second, sort=sort)
+        case = box(second.values)
+        result = first.union(case, sort=sort)
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize("tz", tz)
+    def test_union(self, tz, sort):
+        rng1 = date_range("1/1/2000", freq="D", periods=5, tz=tz)
+        other1 = date_range("1/6/2000", freq="D", periods=5, tz=tz)
+        expected1 = date_range("1/1/2000", freq="D", periods=10, tz=tz)
+        expected1_notsorted = DatetimeIndex(list(other1) + list(rng1))
+
+        rng2 = date_range("1/1/2000", freq="D", periods=5, tz=tz)
+        other2 = date_range("1/4/2000", freq="D", periods=5, tz=tz)
+        expected2 = date_range("1/1/2000", freq="D", periods=8, tz=tz)
+        expected2_notsorted = DatetimeIndex(list(other2) + list(rng2[:3]))
+
+        rng3 = date_range("1/1/2000", freq="D", periods=5, tz=tz)
+        other3 = DatetimeIndex([], tz=tz).as_unit("ns")
+        expected3 = date_range("1/1/2000", freq="D", periods=5, tz=tz)
+        expected3_notsorted = rng3
+
+        for rng, other, exp, exp_notsorted in [
+            (rng1, other1, expected1, expected1_notsorted),
+            (rng2, other2, expected2, expected2_notsorted),
+            (rng3, other3, expected3, expected3_notsorted),
+        ]:
+            result_union = rng.union(other, sort=sort)
+            tm.assert_index_equal(result_union, exp)
+
+            result_union = other.union(rng, sort=sort)
+            if sort is None:
+                tm.assert_index_equal(result_union, exp)
+            else:
+                tm.assert_index_equal(result_union, exp_notsorted)
+
+    def test_union_coverage(self, sort):
+        idx = DatetimeIndex(["2000-01-03", "2000-01-01", "2000-01-02"])
+        ordered = DatetimeIndex(idx.sort_values(), freq="infer")
+        result = ordered.union(idx, sort=sort)
+        tm.assert_index_equal(result, ordered)
+
+        result = ordered[:0].union(ordered, sort=sort)
+        tm.assert_index_equal(result, ordered)
+        assert result.freq == ordered.freq
+
+    def test_union_bug_1730(self, sort):
+        rng_a = date_range("1/1/2012", periods=4, freq="3h")
+        rng_b = date_range("1/1/2012", periods=4, freq="4h")
+
+        result = rng_a.union(rng_b, sort=sort)
+        exp = list(rng_a) + list(rng_b[1:])
+        if sort is None:
+            exp = DatetimeIndex(sorted(exp))
+        else:
+            exp = DatetimeIndex(exp)
+        tm.assert_index_equal(result, exp)
+
+    def test_union_bug_1745(self, sort):
+        left = DatetimeIndex(["2012-05-11 15:19:49.695000"])
+        right = DatetimeIndex(
+            [
+                "2012-05-29 13:04:21.322000",
+                "2012-05-11 15:27:24.873000",
+                "2012-05-11 15:31:05.350000",
+            ]
+        )
+
+        result = left.union(right, sort=sort)
+        exp = DatetimeIndex(
+            [
+                "2012-05-11 15:19:49.695000",
+                "2012-05-29 13:04:21.322000",
+                "2012-05-11 15:27:24.873000",
+                "2012-05-11 15:31:05.350000",
+            ]
+        )
+        if sort is None:
+            exp = exp.sort_values()
+        tm.assert_index_equal(result, exp)
+
+    def test_union_bug_4564(self, sort):
+        from pandas import DateOffset
+
+        left = date_range("2013-01-01", "2013-02-01")
+        right = left + DateOffset(minutes=15)
+
+        result = left.union(right, sort=sort)
+        exp = list(left) + list(right)
+        if sort is None:
+            exp = DatetimeIndex(sorted(exp))
+        else:
+            exp = DatetimeIndex(exp)
+        tm.assert_index_equal(result, exp)
+
+    def test_union_freq_both_none(self, sort):
+        # GH11086
+        expected = bdate_range("20150101", periods=10)
+        expected._data.freq = None
+
+        result = expected.union(expected, sort=sort)
+        tm.assert_index_equal(result, expected)
+        assert result.freq is None
+
+    def test_union_freq_infer(self):
+        # When taking the union of two DatetimeIndexes, we infer
+        #  a freq even if the arguments don't have freq.  This matches
+        #  TimedeltaIndex behavior.
+        dti = date_range("2016-01-01", periods=5)
+        left = dti[[0, 1, 3, 4]]
+        right = dti[[2, 3, 1]]
+
+        assert left.freq is None
+        assert right.freq is None
+
+        result = left.union(right)
+        tm.assert_index_equal(result, dti)
+        assert result.freq == "D"
+
+    def test_union_dataframe_index(self):
+        rng1 = date_range("1/1/1999", "1/1/2012", freq="MS")
+        s1 = Series(np.random.default_rng(2).standard_normal(len(rng1)), rng1)
+
+        rng2 = date_range("1/1/1980", "12/1/2001", freq="MS")
+        s2 = Series(np.random.default_rng(2).standard_normal(len(rng2)), rng2)
+        df = DataFrame({"s1": s1, "s2": s2})
+
+        exp = date_range("1/1/1980", "1/1/2012", freq="MS")
+        tm.assert_index_equal(df.index, exp)
+
+    def test_union_with_DatetimeIndex(self, sort):
+        i1 = Index(np.arange(0, 20, 2, dtype=np.int64))
+        i2 = date_range(start="2012-01-03 00:00:00", periods=10, freq="D")
+        # Works
+        i1.union(i2, sort=sort)
+        # Fails with "AttributeError: can't set attribute"
+        i2.union(i1, sort=sort)
+
+    def test_union_same_timezone_different_units(self):
+        # GH 55238
+        idx1 = date_range("2000-01-01", periods=3, tz="UTC").as_unit("ms")
+        idx2 = date_range("2000-01-01", periods=3, tz="UTC").as_unit("us")
+        result = idx1.union(idx2)
+        expected = date_range("2000-01-01", periods=3, tz="UTC").as_unit("us")
+        tm.assert_index_equal(result, expected)
+
+    # TODO: moved from test_datetimelike; de-duplicate with version below
+    def test_intersection2(self):
+        first = date_range("2020-01-01", periods=10)
+        second = first[5:]
+        intersect = first.intersection(second)
+        tm.assert_index_equal(intersect, second)
+
+        # GH 10149
+        cases = [klass(second.values) for klass in [np.array, Series, list]]
+        for case in cases:
+            result = first.intersection(case)
+            tm.assert_index_equal(result, second)
+
+        third = Index(["a", "b", "c"])
+        result = first.intersection(third)
+        expected = Index([], dtype=object)
+        tm.assert_index_equal(result, expected)
+
+    @pytest.mark.parametrize(
+        "tz", [None, "Asia/Tokyo", "US/Eastern", "dateutil/US/Pacific"]
+    )
+    def test_intersection(self, tz, sort):
+        # GH 4690 (with tz)
+        base = date_range("6/1/2000", "6/30/2000", freq="D", name="idx")
+
+        # if target has the same name, it is preserved
+        rng2 = date_range("5/15/2000", "6/20/2000", freq="D", name="idx")
+        expected2 = date_range("6/1/2000", "6/20/2000", freq="D", name="idx")
+
+        # if target name is different, it will be reset
+        rng3 = date_range("5/15/2000", "6/20/2000", freq="D", name="other")
+        expected3 = date_range("6/1/2000", "6/20/2000", freq="D", name=None)
+
+        rng4 = date_range("7/1/2000", "7/31/2000", freq="D", name="idx")
+        expected4 = DatetimeIndex([], freq="D", name="idx", dtype="M8[ns]")
+
+        for rng, expected in [
+            (rng2, expected2),
+            (rng3, expected3),
+            (rng4, expected4),
+        ]:
+            result = base.intersection(rng)
+            tm.assert_index_equal(result, expected)
+            assert result.freq == expected.freq
+
+        # non-monotonic
+        base = DatetimeIndex(
+            ["2011-01-05", "2011-01-04", "2011-01-02", "2011-01-03"], tz=tz, name="idx"
+        ).as_unit("ns")
+
+        rng2 = DatetimeIndex(
+            ["2011-01-04", "2011-01-02", "2011-02-02", "2011-02-03"], tz=tz, name="idx"
+        ).as_unit("ns")
+        expected2 = DatetimeIndex(
+            ["2011-01-04", "2011-01-02"], tz=tz, name="idx"
+        ).as_unit("ns")
+
+        rng3 = DatetimeIndex(
+            ["2011-01-04", "2011-01-02", "2011-02-02", "2011-02-03"],
+            tz=tz,
+            name="other",
+        ).as_unit("ns")
+        expected3 = DatetimeIndex(
+            ["2011-01-04", "2011-01-02"], tz=tz, name=None
+        ).as_unit("ns")
+
+        # GH 7880
+        rng4 = date_range("7/1/2000", "7/31/2000", freq="D", tz=tz, name="idx")
+        expected4 = DatetimeIndex([], tz=tz, name="idx").as_unit("ns")
+        assert expected4.freq is None
+
+        for rng, expected in [
+            (rng2, expected2),
+            (rng3, expected3),
+            (rng4, expected4),
+        ]:
+            result = base.intersection(rng, sort=sort)
+            if sort is None:
+                expected = expected.sort_values()
+            tm.assert_index_equal(result, expected)
+            assert result.freq == expected.freq
+
+    # parametrize over both anchored and non-anchored freqs, as they
+    #  have different code paths
+    @pytest.mark.parametrize("freq", ["min", "B"])
+    def test_intersection_empty(self, tz_aware_fixture, freq):
+        # empty same freq GH2129
+        tz = tz_aware_fixture
+        rng = date_range("6/1/2000", "6/15/2000", freq=freq, tz=tz)
+        result = rng[0:0].intersection(rng)
+        assert len(result) == 0
+        assert result.freq == rng.freq
+
+        result = rng.intersection(rng[0:0])
+        assert len(result) == 0
+        assert result.freq == rng.freq
+
+        # no overlap GH#33604
+        check_freq = freq != "min"  # We don't preserve freq on non-anchored offsets
+        result = rng[:3].intersection(rng[-3:])
+        tm.assert_index_equal(result, rng[:0])
+        if check_freq:
+            # We don't preserve freq on non-anchored offsets
+            assert result.freq == rng.freq
+
+        # swapped left and right
+        result = rng[-3:].intersection(rng[:3])
+        tm.assert_index_equal(result, rng[:0])
+        if check_freq:
+            # We don't preserve freq on non-anchored offsets
+            assert result.freq == rng.freq
+
+    def test_intersection_bug_1708(self):
+        from pandas import DateOffset
+
+        index_1 = date_range("1/1/2012", periods=4, freq="12h")
+        index_2 = index_1 + DateOffset(hours=1)
+
+        result = index_1.intersection(index_2)
+        assert len(result) == 0
+
+    @pytest.mark.parametrize("tz", tz)
+    def test_difference(self, tz, sort):
+        rng_dates = ["1/2/2000", "1/3/2000", "1/1/2000", "1/4/2000", "1/5/2000"]
+
+        rng1 = DatetimeIndex(rng_dates, tz=tz)
+        other1 = date_range("1/6/2000", freq="D", periods=5, tz=tz)
+        expected1 = DatetimeIndex(rng_dates, tz=tz)
+
+        rng2 = DatetimeIndex(rng_dates, tz=tz)
+        other2 = date_range("1/4/2000", freq="D", periods=5, tz=tz)
+        expected2 = DatetimeIndex(rng_dates[:3], tz=tz)
+
+        rng3 = DatetimeIndex(rng_dates, tz=tz)
+        other3 = DatetimeIndex([], tz=tz)
+        expected3 = DatetimeIndex(rng_dates, tz=tz)
+
+        for rng, other, expected in [
+            (rng1, other1, expected1),
+            (rng2, other2, expected2),
+            (rng3, other3, expected3),
+        ]:
+            result_diff = rng.difference(other, sort)
+            if sort is None and len(other):
+                # We dont sort (yet?) when empty GH#24959
+                expected = expected.sort_values()
+            tm.assert_index_equal(result_diff, expected)
+
+    def test_difference_freq(self, sort):
+        # GH14323: difference of DatetimeIndex should not preserve frequency
+
+        index = date_range("20160920", "20160925", freq="D")
+        other = date_range("20160921", "20160924", freq="D")
+        expected = DatetimeIndex(["20160920", "20160925"], dtype="M8[ns]", freq=None)
+        idx_diff = index.difference(other, sort)
+        tm.assert_index_equal(idx_diff, expected)
+        tm.assert_attr_equal("freq", idx_diff, expected)
+
+        # preserve frequency when the difference is a contiguous
+        # subset of the original range
+        other = date_range("20160922", "20160925", freq="D")
+        idx_diff = index.difference(other, sort)
+        expected = DatetimeIndex(["20160920", "20160921"], dtype="M8[ns]", freq="D")
+        tm.assert_index_equal(idx_diff, expected)
+        tm.assert_attr_equal("freq", idx_diff, expected)
+
+    def test_datetimeindex_diff(self, sort):
+        dti1 = date_range(freq="QE-JAN", start=datetime(1997, 12, 31), periods=100)
+        dti2 = date_range(freq="QE-JAN", start=datetime(1997, 12, 31), periods=98)
+        assert len(dti1.difference(dti2, sort)) == 2
+
+    @pytest.mark.parametrize("tz", [None, "Asia/Tokyo", "US/Eastern"])
+    def test_setops_preserve_freq(self, tz):
+        rng = date_range("1/1/2000", "1/1/2002", name="idx", tz=tz)
+
+        result = rng[:50].union(rng[50:100])
+        assert result.name == rng.name
+        assert result.freq == rng.freq
+        assert result.tz == rng.tz
+
+        result = rng[:50].union(rng[30:100])
+        assert result.name == rng.name
+        assert result.freq == rng.freq
+        assert result.tz == rng.tz
+
+        result = rng[:50].union(rng[60:100])
+        assert result.name == rng.name
+        assert result.freq is None
+        assert result.tz == rng.tz
+
+        result = rng[:50].intersection(rng[25:75])
+        assert result.name == rng.name
+        assert result.freqstr == "D"
+        assert result.tz == rng.tz
+
+        nofreq = DatetimeIndex(list(rng[25:75]), name="other")
+        result = rng[:50].union(nofreq)
+        assert result.name is None
+        assert result.freq == rng.freq
+        assert result.tz == rng.tz
+
+        result = rng[:50].intersection(nofreq)
+        assert result.name is None
+        assert result.freq == rng.freq
+        assert result.tz == rng.tz
+
+    def test_intersection_non_tick_no_fastpath(self):
+        # GH#42104
+        dti = DatetimeIndex(
+            [
+                "2018-12-31",
+                "2019-03-31",
+                "2019-06-30",
+                "2019-09-30",
+                "2019-12-31",
+                "2020-03-31",
+            ],
+            freq="QE-DEC",
+        )
+        result = dti[::2].intersection(dti[1::2])
+        expected = dti[:0]
+        tm.assert_index_equal(result, expected)
+
+    def test_dti_intersection(self):
+        rng = date_range("1/1/2011", periods=100, freq="h", tz="utc")
+
+        left = rng[10:90][::-1]
+        right = rng[20:80][::-1]
+
+        assert left.tz == rng.tz
+        result = left.intersection(right)
+        assert result.tz == left.tz
+
+    # Note: not difference, as there is no symmetry requirement there
+    @pytest.mark.parametrize("setop", ["union", "intersection", "symmetric_difference"])
+    def test_dti_setop_aware(self, setop):
+        # non-overlapping
+        # GH#39328 as of 2.0 we cast these to UTC instead of object
+        rng = date_range("2012-11-15 00:00:00", periods=6, freq="h", tz="US/Central")
+
+        rng2 = date_range("2012-11-15 12:00:00", periods=6, freq="h", tz="US/Eastern")
+
+        result = getattr(rng, setop)(rng2)
+
+        left = rng.tz_convert("UTC")
+        right = rng2.tz_convert("UTC")
+        expected = getattr(left, setop)(right)
+        tm.assert_index_equal(result, expected)
+        assert result.tz == left.tz
+        if len(result):
+            assert result[0].tz is timezone.utc
+            assert result[-1].tz is timezone.utc
+
+    def test_dti_union_mixed(self):
+        # GH#21671
+        rng = DatetimeIndex([Timestamp("2011-01-01"), pd.NaT])
+        rng2 = DatetimeIndex(["2012-01-01", "2012-01-02"], tz="Asia/Tokyo")
+        result = rng.union(rng2)
+        expected = Index(
+            [
+                Timestamp("2011-01-01"),
+                pd.NaT,
+                Timestamp("2012-01-01", tz="Asia/Tokyo"),
+                Timestamp("2012-01-02", tz="Asia/Tokyo"),
+            ],
+            dtype=object,
+        )
+        tm.assert_index_equal(result, expected)
+
+
+class TestBusinessDatetimeIndex:
+    def test_union(self, sort):
+        rng = bdate_range(START, END)
+        # overlapping
+        left = rng[:10]
+        right = rng[5:10]
+
+        the_union = left.union(right, sort=sort)
+        assert isinstance(the_union, DatetimeIndex)
+
+        # non-overlapping, gap in middle
+        left = rng[:5]
+        right = rng[10:]
+
+        the_union = left.union(right, sort=sort)
+        assert isinstance(the_union, Index)
+
+        # non-overlapping, no gap
+        left = rng[:5]
+        right = rng[5:10]
+
+        the_union = left.union(right, sort=sort)
+        assert isinstance(the_union, DatetimeIndex)
+
+        # order does not matter
+        if sort is None:
+            tm.assert_index_equal(right.union(left, sort=sort), the_union)
+        else:
+            expected = DatetimeIndex(list(right) + list(left))
+            tm.assert_index_equal(right.union(left, sort=sort), expected)
+
+        # overlapping, but different offset
+        rng = date_range(START, END, freq=BMonthEnd())
+
+        the_union = rng.union(rng, sort=sort)
+        assert isinstance(the_union, DatetimeIndex)
+
+    def test_union_not_cacheable(self, sort):
+        rng = date_range("1/1/2000", periods=50, freq=Minute())
+        rng1 = rng[10:]
+        rng2 = rng[:25]
+        the_union = rng1.union(rng2, sort=sort)
+        if sort is None:
+            tm.assert_index_equal(the_union, rng)
+        else:
+            expected = DatetimeIndex(list(rng[10:]) + list(rng[:10]))
+            tm.assert_index_equal(the_union, expected)
+
+        rng1 = rng[10:]
+        rng2 = rng[15:35]
+        the_union = rng1.union(rng2, sort=sort)
+        expected = rng[10:]
+        tm.assert_index_equal(the_union, expected)
+
+    def test_intersection(self):
+        rng = date_range("1/1/2000", periods=50, freq=Minute())
+        rng1 = rng[10:]
+        rng2 = rng[:25]
+        the_int = rng1.intersection(rng2)
+        expected = rng[10:25]
+        tm.assert_index_equal(the_int, expected)
+        assert isinstance(the_int, DatetimeIndex)
+        assert the_int.freq == rng.freq
+
+        the_int = rng1.intersection(rng2)
+        tm.assert_index_equal(the_int, expected)
+
+        # non-overlapping
+        the_int = rng[:10].intersection(rng[10:])
+        expected = DatetimeIndex([]).as_unit("ns")
+        tm.assert_index_equal(the_int, expected)
+
+    def test_intersection_bug(self):
+        # GH #771
+        a = bdate_range("11/30/2011", "12/31/2011")
+        b = bdate_range("12/10/2011", "12/20/2011")
+        result = a.intersection(b)
+        tm.assert_index_equal(result, b)
+        assert result.freq == b.freq
+
+    def test_intersection_list(self):
+        # GH#35876
+        # values is not an Index -> no name -> retain "a"
+        values = [Timestamp("2020-01-01"), Timestamp("2020-02-01")]
+        idx = DatetimeIndex(values, name="a")
+        res = idx.intersection(values)
+        tm.assert_index_equal(res, idx)
+
+    def test_month_range_union_tz_pytz(self, sort):
+        tz = pytz.timezone("US/Eastern")
+
+        early_start = datetime(2011, 1, 1)
+        early_end = datetime(2011, 3, 1)
+
+        late_start = datetime(2011, 3, 1)
+        late_end = datetime(2011, 5, 1)
+
+        early_dr = date_range(start=early_start, end=early_end, tz=tz, freq=MonthEnd())
+        late_dr = date_range(start=late_start, end=late_end, tz=tz, freq=MonthEnd())
+
+        early_dr.union(late_dr, sort=sort)
+
+    @td.skip_if_windows
+    def test_month_range_union_tz_dateutil(self, sort):
+        from pandas._libs.tslibs.timezones import dateutil_gettz
+
+        tz = dateutil_gettz("US/Eastern")
+
+        early_start = datetime(2011, 1, 1)
+        early_end = datetime(2011, 3, 1)
+
+        late_start = datetime(2011, 3, 1)
+        late_end = datetime(2011, 5, 1)
+
+        early_dr = date_range(start=early_start, end=early_end, tz=tz, freq=MonthEnd())
+        late_dr = date_range(start=late_start, end=late_end, tz=tz, freq=MonthEnd())
+
+        early_dr.union(late_dr, sort=sort)
+
+    @pytest.mark.parametrize("sort", [False, None])
+    def test_intersection_duplicates(self, sort):
+        # GH#38196
+        idx1 = Index(
+            [
+                Timestamp("2019-12-13"),
+                Timestamp("2019-12-12"),
+                Timestamp("2019-12-12"),
+            ]
+        )
+        result = idx1.intersection(idx1, sort=sort)
+        expected = Index([Timestamp("2019-12-13"), Timestamp("2019-12-12")])
+        tm.assert_index_equal(result, expected)
+
+
+class TestCustomDatetimeIndex:
+    def test_union(self, sort):
+        # overlapping
+        rng = bdate_range(START, END, freq="C")
+        left = rng[:10]
+        right = rng[5:10]
+
+        the_union = left.union(right, sort=sort)
+        assert isinstance(the_union, DatetimeIndex)
+
+        # non-overlapping, gap in middle
+        left = rng[:5]
+        right = rng[10:]
+
+        the_union = left.union(right, sort)
+        assert isinstance(the_union, Index)
+
+        # non-overlapping, no gap
+        left = rng[:5]
+        right = rng[5:10]
+
+        the_union = left.union(right, sort=sort)
+        assert isinstance(the_union, DatetimeIndex)
+
+        # order does not matter
+        if sort is None:
+            tm.assert_index_equal(right.union(left, sort=sort), the_union)
+
+        # overlapping, but different offset
+        rng = date_range(START, END, freq=BMonthEnd())
+
+        the_union = rng.union(rng, sort=sort)
+        assert isinstance(the_union, DatetimeIndex)
+
+    def test_intersection_bug(self):
+        # GH #771
+        a = bdate_range("11/30/2011", "12/31/2011", freq="C")
+        b = bdate_range("12/10/2011", "12/20/2011", freq="C")
+        result = a.intersection(b)
+        tm.assert_index_equal(result, b)
+        assert result.freq == b.freq
+
+    @pytest.mark.parametrize(
+        "tz", [None, "UTC", "Europe/Berlin", pytz.FixedOffset(-60)]
+    )
+    def test_intersection_dst_transition(self, tz):
+        # GH 46702: Europe/Berlin has DST transition
+        idx1 = date_range("2020-03-27", periods=5, freq="D", tz=tz)
+        idx2 = date_range("2020-03-30", periods=5, freq="D", tz=tz)
+        result = idx1.intersection(idx2)
+        expected = date_range("2020-03-30", periods=2, freq="D", tz=tz)
+        tm.assert_index_equal(result, expected)
+
+        # GH#45863 same problem for union
+        index1 = date_range("2021-10-28", periods=3, freq="D", tz="Europe/London")
+        index2 = date_range("2021-10-30", periods=4, freq="D", tz="Europe/London")
+        result = index1.union(index2)
+        expected = date_range("2021-10-28", periods=6, freq="D", tz="Europe/London")
+        tm.assert_index_equal(result, expected)

venv/lib/python3.10/site-packages/pandas/tests/indexes/datetimes/test_timezones.py

@@ -0,0 +1,251 @@
+"""
+Tests for DatetimeIndex timezone-related methods
+"""
+from datetime import (
+    datetime,
+    timedelta,
+    timezone,
+    tzinfo,
+)
+
+from dateutil.tz import gettz
+import numpy as np
+import pytest
+import pytz
+
+from pandas._libs.tslibs import (
+    conversion,
+    timezones,
+)
+
+import pandas as pd
+from pandas import (
+    DatetimeIndex,
+    Timestamp,
+    bdate_range,
+    date_range,
+    isna,
+    to_datetime,
+)
+import pandas._testing as tm
+
+
+class FixedOffset(tzinfo):
+    """Fixed offset in minutes east from UTC."""
+
+    def __init__(self, offset, name) -> None:
+        self.__offset = timedelta(minutes=offset)
+        self.__name = name
+
+    def utcoffset(self, dt):
+        return self.__offset
+
+    def tzname(self, dt):
+        return self.__name
+
+    def dst(self, dt):
+        return timedelta(0)
+
+
+fixed_off_no_name = FixedOffset(-330, None)
+
+
+class TestDatetimeIndexTimezones:
+    # -------------------------------------------------------------
+    # Unsorted
+
+    def test_dti_drop_dont_lose_tz(self):
+        # GH#2621
+        ind = date_range("2012-12-01", periods=10, tz="utc")
+        ind = ind.drop(ind[-1])
+
+        assert ind.tz is not None
+
+    def test_dti_tz_conversion_freq(self, tz_naive_fixture):
+        # GH25241
+        t3 = DatetimeIndex(["2019-01-01 10:00"], freq="h")
+        assert t3.tz_localize(tz=tz_naive_fixture).freq == t3.freq
+        t4 = DatetimeIndex(["2019-01-02 12:00"], tz="UTC", freq="min")
+        assert t4.tz_convert(tz="UTC").freq == t4.freq
+
+    def test_drop_dst_boundary(self):
+        # see gh-18031
+        tz = "Europe/Brussels"
+        freq = "15min"
+
+        start = Timestamp("201710290100", tz=tz)
+        end = Timestamp("201710290300", tz=tz)
+        index = date_range(start=start, end=end, freq=freq)
+
+        expected = DatetimeIndex(
+            [
+                "201710290115",
+                "201710290130",
+                "201710290145",
+                "201710290200",
+                "201710290215",
+                "201710290230",
+                "201710290245",
+                "201710290200",
+                "201710290215",
+                "201710290230",
+                "201710290245",
+                "201710290300",
+            ],
+            dtype="M8[ns, Europe/Brussels]",
+            freq=freq,
+            ambiguous=[
+                True,
+                True,
+                True,
+                True,
+                True,
+                True,
+                True,
+                False,
+                False,
+                False,
+                False,
+                False,
+            ],
+        )
+        result = index.drop(index[0])
+        tm.assert_index_equal(result, expected)
+
+    def test_date_range_localize(self, unit):
+        rng = date_range(
+            "3/11/2012 03:00", periods=15, freq="h", tz="US/Eastern", unit=unit
+        )
+        rng2 = DatetimeIndex(
+            ["3/11/2012 03:00", "3/11/2012 04:00"], dtype=f"M8[{unit}, US/Eastern]"
+        )
+        rng3 = date_range("3/11/2012 03:00", periods=15, freq="h", unit=unit)
+        rng3 = rng3.tz_localize("US/Eastern")
+
+        tm.assert_index_equal(rng._with_freq(None), rng3)
+
+        # DST transition time
+        val = rng[0]
+        exp = Timestamp("3/11/2012 03:00", tz="US/Eastern")
+
+        assert val.hour == 3
+        assert exp.hour == 3
+        assert val == exp  # same UTC value
+        tm.assert_index_equal(rng[:2], rng2)
+
+    def test_date_range_localize2(self, unit):
+        # Right before the DST transition
+        rng = date_range(
+            "3/11/2012 00:00", periods=2, freq="h", tz="US/Eastern", unit=unit
+        )
+        rng2 = DatetimeIndex(
+            ["3/11/2012 00:00", "3/11/2012 01:00"],
+            dtype=f"M8[{unit}, US/Eastern]",
+            freq="h",
+        )
+        tm.assert_index_equal(rng, rng2)
+        exp = Timestamp("3/11/2012 00:00", tz="US/Eastern")
+        assert exp.hour == 0
+        assert rng[0] == exp
+        exp = Timestamp("3/11/2012 01:00", tz="US/Eastern")
+        assert exp.hour == 1
+        assert rng[1] == exp
+
+        rng = date_range(
+            "3/11/2012 00:00", periods=10, freq="h", tz="US/Eastern", unit=unit
+        )
+        assert rng[2].hour == 3
+
+    def test_timestamp_equality_different_timezones(self):
+        utc_range = date_range("1/1/2000", periods=20, tz="UTC")
+        eastern_range = utc_range.tz_convert("US/Eastern")
+        berlin_range = utc_range.tz_convert("Europe/Berlin")
+
+        for a, b, c in zip(utc_range, eastern_range, berlin_range):
+            assert a == b
+            assert b == c
+            assert a == c
+
+        assert (utc_range == eastern_range).all()
+        assert (utc_range == berlin_range).all()
+        assert (berlin_range == eastern_range).all()
+
+    def test_dti_equals_with_tz(self):
+        left = date_range("1/1/2011", periods=100, freq="h", tz="utc")
+        right = date_range("1/1/2011", periods=100, freq="h", tz="US/Eastern")
+
+        assert not left.equals(right)
+
+    @pytest.mark.parametrize("tzstr", ["US/Eastern", "dateutil/US/Eastern"])
+    def test_dti_tz_nat(self, tzstr):
+        idx = DatetimeIndex([Timestamp("2013-1-1", tz=tzstr), pd.NaT])
+
+        assert isna(idx[1])
+        assert idx[0].tzinfo is not None
+
+    @pytest.mark.parametrize("tzstr", ["US/Eastern", "dateutil/US/Eastern"])
+    def test_utc_box_timestamp_and_localize(self, tzstr):
+        tz = timezones.maybe_get_tz(tzstr)
+
+        rng = date_range("3/11/2012", "3/12/2012", freq="h", tz="utc")
+        rng_eastern = rng.tz_convert(tzstr)
+
+        expected = rng[-1].astimezone(tz)
+
+        stamp = rng_eastern[-1]
+        assert stamp == expected
+        assert stamp.tzinfo == expected.tzinfo
+
+        # right tzinfo
+        rng = date_range("3/13/2012", "3/14/2012", freq="h", tz="utc")
+        rng_eastern = rng.tz_convert(tzstr)
+        # test not valid for dateutil timezones.
+        # assert 'EDT' in repr(rng_eastern[0].tzinfo)
+        assert "EDT" in repr(rng_eastern[0].tzinfo) or "tzfile" in repr(
+            rng_eastern[0].tzinfo
+        )
+
+    @pytest.mark.parametrize("tz", [pytz.timezone("US/Central"), gettz("US/Central")])
+    def test_with_tz(self, tz):
+        # just want it to work
+        start = datetime(2011, 3, 12, tzinfo=pytz.utc)
+        dr = bdate_range(start, periods=50, freq=pd.offsets.Hour())
+        assert dr.tz is pytz.utc
+
+        # DateRange with naive datetimes
+        dr = bdate_range("1/1/2005", "1/1/2009", tz=pytz.utc)
+        dr = bdate_range("1/1/2005", "1/1/2009", tz=tz)
+
+        # normalized
+        central = dr.tz_convert(tz)
+        assert central.tz is tz
+        naive = central[0].to_pydatetime().replace(tzinfo=None)
+        comp = conversion.localize_pydatetime(naive, tz).tzinfo
+        assert central[0].tz is comp
+
+        # compare vs a localized tz
+        naive = dr[0].to_pydatetime().replace(tzinfo=None)
+        comp = conversion.localize_pydatetime(naive, tz).tzinfo
+        assert central[0].tz is comp
+
+        # datetimes with tzinfo set
+        dr = bdate_range(
+            datetime(2005, 1, 1, tzinfo=pytz.utc), datetime(2009, 1, 1, tzinfo=pytz.utc)
+        )
+        msg = "Start and end cannot both be tz-aware with different timezones"
+        with pytest.raises(Exception, match=msg):
+            bdate_range(datetime(2005, 1, 1, tzinfo=pytz.utc), "1/1/2009", tz=tz)
+
+    @pytest.mark.parametrize("tz", [pytz.timezone("US/Eastern"), gettz("US/Eastern")])
+    def test_dti_convert_tz_aware_datetime_datetime(self, tz):
+        # GH#1581
+        dates = [datetime(2000, 1, 1), datetime(2000, 1, 2), datetime(2000, 1, 3)]
+
+        dates_aware = [conversion.localize_pydatetime(x, tz) for x in dates]
+        result = DatetimeIndex(dates_aware).as_unit("ns")
+        assert timezones.tz_compare(result.tz, tz)
+
+        converted = to_datetime(dates_aware, utc=True).as_unit("ns")
+        ex_vals = np.array([Timestamp(x).as_unit("ns")._value for x in dates_aware])
+        tm.assert_numpy_array_equal(converted.asi8, ex_vals)
+        assert converted.tz is timezone.utc