diff --git "a/venv/lib/python3.10/site-packages/multiprocess/tests/__init__.py" "b/venv/lib/python3.10/site-packages/multiprocess/tests/__init__.py"
new file mode 100644--- /dev/null
+++ "b/venv/lib/python3.10/site-packages/multiprocess/tests/__init__.py"
@@ -0,0 +1,6000 @@
+#
+# Unit tests for the multiprocessing package
+#
+
+import unittest
+import unittest.mock
+import queue as pyqueue
+import textwrap
+import time
+import io
+import itertools
+import sys
+import os
+import gc
+import errno
+import signal
+import array
+import socket
+import random
+import logging
+import subprocess
+import struct
+import operator
+import pickle #XXX: use dill?
+import weakref
+import warnings
+import test.support
+import test.support.script_helper
+from test import support
+from test.support import hashlib_helper
+from test.support import import_helper
+from test.support import os_helper
+from test.support import socket_helper
+from test.support import threading_helper
+from test.support import warnings_helper
+
+
+# Skip tests if _multiprocessing wasn't built.
+_multiprocessing = import_helper.import_module('_multiprocessing')
+# Skip tests if sem_open implementation is broken.
+import_helper.import_module('multiprocess.synchronize')
+import threading
+
+import multiprocess as multiprocessing
+import multiprocess.connection
+import multiprocess.dummy
+import multiprocess.heap
+import multiprocess.managers
+import multiprocess.pool
+import multiprocess.queues
+
+from multiprocess import util
+
+try:
+    from multiprocess import reduction
+    HAS_REDUCTION = reduction.HAVE_SEND_HANDLE
+except ImportError:
+    HAS_REDUCTION = False
+
+try:
+    from multiprocess.sharedctypes import Value, copy
+    HAS_SHAREDCTYPES = True
+except ImportError:
+    HAS_SHAREDCTYPES = False
+
+try:
+    from multiprocess import shared_memory
+    HAS_SHMEM = True
+except ImportError:
+    HAS_SHMEM = False
+
+try:
+    import msvcrt
+except ImportError:
+    msvcrt = None
+
+
+if hasattr(support,'check_sanitizer') and support.check_sanitizer(address=True):
+    # bpo-45200: Skip multiprocessing tests if Python is built with ASAN to
+    # work around a libasan race condition: dead lock in pthread_create().
+    raise unittest.SkipTest("libasan has a pthread_create() dead lock")
+
+# Don't ignore user's installed packages
+ENV = dict(__cleanenv = False, __isolated = False)
+
+# Timeout to wait until a process completes #XXX: travis-ci
+TIMEOUT = (90.0 if os.environ.get('COVERAGE') else 60.0) # seconds
+
+def latin(s):
+    return s.encode('latin')
+
+
+def close_queue(queue):
+    if isinstance(queue, multiprocessing.queues.Queue):
+        queue.close()
+        queue.join_thread()
+
+
+def join_process(process):
+    # Since multiprocessing.Process has the same API than threading.Thread
+    # (join() and is_alive(), the support function can be reused
+    threading_helper.join_thread(process, timeout=TIMEOUT)
+
+
+if os.name == "posix":
+    from multiprocess import resource_tracker
+
+    def _resource_unlink(name, rtype):
+        resource_tracker._CLEANUP_FUNCS[rtype](name)
+
+
+#
+# Constants
+#
+
+LOG_LEVEL = util.SUBWARNING
+#LOG_LEVEL = logging.DEBUG
+
+DELTA = 0.1
+CHECK_TIMINGS = False     # making true makes tests take a lot longer
+                          # and can sometimes cause some non-serious
+                          # failures because some calls block a bit
+                          # longer than expected
+if CHECK_TIMINGS:
+    TIMEOUT1, TIMEOUT2, TIMEOUT3 = 0.82, 0.35, 1.4
+else:
+    TIMEOUT1, TIMEOUT2, TIMEOUT3 = 0.1, 0.1, 0.1
+
+HAVE_GETVALUE = not getattr(_multiprocessing,
+                            'HAVE_BROKEN_SEM_GETVALUE', False)
+
+WIN32 = (sys.platform == "win32")
+
+from multiprocess.connection import wait
+
+def wait_for_handle(handle, timeout):
+    if timeout is not None and timeout < 0.0:
+        timeout = None
+    return wait([handle], timeout)
+
+try:
+    MAXFD = os.sysconf("SC_OPEN_MAX")
+except:
+    MAXFD = 256
+
+# To speed up tests when using the forkserver, we can preload these:
+PRELOAD = ['__main__', 'test_multiprocessing_forkserver']
+
+#
+# Some tests require ctypes
+#
+
+try:
+    from ctypes import Structure, c_int, c_double, c_longlong
+except ImportError:
+    Structure = object
+    c_int = c_double = c_longlong = None
+
+
+def check_enough_semaphores():
+    """Check that the system supports enough semaphores to run the test."""
+    # minimum number of semaphores available according to POSIX
+    nsems_min = 256
+    try:
+        nsems = os.sysconf("SC_SEM_NSEMS_MAX")
+    except (AttributeError, ValueError):
+        # sysconf not available or setting not available
+        return
+    if nsems == -1 or nsems >= nsems_min:
+        return
+    raise unittest.SkipTest("The OS doesn't support enough semaphores "
+                            "to run the test (required: %d)." % nsems_min)
+
+
+#
+# Creates a wrapper for a function which records the time it takes to finish
+#
+
+class TimingWrapper(object):
+
+    def __init__(self, func):
+        self.func = func
+        self.elapsed = None
+
+    def __call__(self, *args, **kwds):
+        t = time.monotonic()
+        try:
+            return self.func(*args, **kwds)
+        finally:
+            self.elapsed = time.monotonic() - t
+
+#
+# Base class for test cases
+#
+
+class BaseTestCase(object):
+
+    ALLOWED_TYPES = ('processes', 'manager', 'threads')
+
+    def assertTimingAlmostEqual(self, a, b):
+        if CHECK_TIMINGS:
+            self.assertAlmostEqual(a, b, 1)
+
+    def assertReturnsIfImplemented(self, value, func, *args):
+        try:
+            res = func(*args)
+        except NotImplementedError:
+            pass
+        else:
+            return self.assertEqual(value, res)
+
+    # For the sanity of Windows users, rather than crashing or freezing in
+    # multiple ways.
+    def __reduce__(self, *args):
+        raise NotImplementedError("shouldn't try to pickle a test case")
+
+    __reduce_ex__ = __reduce__
+
+#
+# Return the value of a semaphore
+#
+
+def get_value(self):
+    try:
+        return self.get_value()
+    except AttributeError:
+        try:
+            return self._Semaphore__value
+        except AttributeError:
+            try:
+                return self._value
+            except AttributeError:
+                raise NotImplementedError
+
+#
+# Testcases
+#
+
+class DummyCallable:
+    def __call__(self, q, c):
+        assert isinstance(c, DummyCallable)
+        q.put(5)
+
+
+class _TestProcess(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes', 'threads')
+
+    def test_current(self):
+        if self.TYPE == 'threads':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        current = self.current_process()
+        authkey = current.authkey
+
+        self.assertTrue(current.is_alive())
+        self.assertTrue(not current.daemon)
+        self.assertIsInstance(authkey, bytes)
+        self.assertTrue(len(authkey) > 0)
+        self.assertEqual(current.ident, os.getpid())
+        self.assertEqual(current.exitcode, None)
+
+    def test_daemon_argument(self):
+        if self.TYPE == "threads":
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        # By default uses the current process's daemon flag.
+        proc0 = self.Process(target=self._test)
+        self.assertEqual(proc0.daemon, self.current_process().daemon)
+        proc1 = self.Process(target=self._test, daemon=True)
+        self.assertTrue(proc1.daemon)
+        proc2 = self.Process(target=self._test, daemon=False)
+        self.assertFalse(proc2.daemon)
+
+    @classmethod
+    def _test(cls, q, *args, **kwds):
+        current = cls.current_process()
+        q.put(args)
+        q.put(kwds)
+        q.put(current.name)
+        if cls.TYPE != 'threads':
+            q.put(bytes(current.authkey))
+            q.put(current.pid)
+
+    def test_parent_process_attributes(self):
+        if self.TYPE == "threads":
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        self.assertIsNone(self.parent_process())
+
+        rconn, wconn = self.Pipe(duplex=False)
+        p = self.Process(target=self._test_send_parent_process, args=(wconn,))
+        p.start()
+        p.join()
+        parent_pid, parent_name = rconn.recv()
+        self.assertEqual(parent_pid, self.current_process().pid)
+        self.assertEqual(parent_pid, os.getpid())
+        self.assertEqual(parent_name, self.current_process().name)
+
+    @classmethod
+    def _test_send_parent_process(cls, wconn):
+        from multiprocess.process import parent_process
+        wconn.send([parent_process().pid, parent_process().name])
+
+    def _test_parent_process(self):
+        if self.TYPE == "threads":
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        # Launch a child process. Make it launch a grandchild process. Kill the
+        # child process and make sure that the grandchild notices the death of
+        # its parent (a.k.a the child process).
+        rconn, wconn = self.Pipe(duplex=False)
+        p = self.Process(
+            target=self._test_create_grandchild_process, args=(wconn, ))
+        p.start()
+
+        if not rconn.poll(timeout=support.LONG_TIMEOUT):
+            raise AssertionError("Could not communicate with child process")
+        parent_process_status = rconn.recv()
+        self.assertEqual(parent_process_status, "alive")
+
+        p.terminate()
+        p.join()
+
+        if not rconn.poll(timeout=support.LONG_TIMEOUT):
+            raise AssertionError("Could not communicate with child process")
+        parent_process_status = rconn.recv()
+        self.assertEqual(parent_process_status, "not alive")
+
+    @classmethod
+    def _test_create_grandchild_process(cls, wconn):
+        p = cls.Process(target=cls._test_report_parent_status, args=(wconn, ))
+        p.start()
+        time.sleep(300)
+
+    @classmethod
+    def _test_report_parent_status(cls, wconn):
+        from multiprocess.process import parent_process
+        wconn.send("alive" if parent_process().is_alive() else "not alive")
+        parent_process().join(timeout=support.SHORT_TIMEOUT)
+        wconn.send("alive" if parent_process().is_alive() else "not alive")
+
+    def test_process(self):
+        q = self.Queue(1)
+        e = self.Event()
+        args = (q, 1, 2)
+        kwargs = {'hello':23, 'bye':2.54}
+        name = 'SomeProcess'
+        p = self.Process(
+            target=self._test, args=args, kwargs=kwargs, name=name
+            )
+        p.daemon = True
+        current = self.current_process()
+
+        if self.TYPE != 'threads':
+            self.assertEqual(p.authkey, current.authkey)
+        self.assertEqual(p.is_alive(), False)
+        self.assertEqual(p.daemon, True)
+        self.assertNotIn(p, self.active_children())
+        self.assertTrue(type(self.active_children()) is list)
+        self.assertEqual(p.exitcode, None)
+
+        p.start()
+
+        self.assertEqual(p.exitcode, None)
+        self.assertEqual(p.is_alive(), True)
+        self.assertIn(p, self.active_children())
+
+        self.assertEqual(q.get(), args[1:])
+        self.assertEqual(q.get(), kwargs)
+        self.assertEqual(q.get(), p.name)
+        if self.TYPE != 'threads':
+            self.assertEqual(q.get(), current.authkey)
+            self.assertEqual(q.get(), p.pid)
+
+        p.join()
+
+        self.assertEqual(p.exitcode, 0)
+        self.assertEqual(p.is_alive(), False)
+        self.assertNotIn(p, self.active_children())
+        close_queue(q)
+
+    @unittest.skipUnless(threading._HAVE_THREAD_NATIVE_ID, "needs native_id")
+    def test_process_mainthread_native_id(self):
+        if self.TYPE == 'threads':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        current_mainthread_native_id = threading.main_thread().native_id
+
+        q = self.Queue(1)
+        p = self.Process(target=self._test_process_mainthread_native_id, args=(q,))
+        p.start()
+
+        child_mainthread_native_id = q.get()
+        p.join()
+        close_queue(q)
+
+        self.assertNotEqual(current_mainthread_native_id, child_mainthread_native_id)
+
+    @classmethod
+    def _test_process_mainthread_native_id(cls, q):
+        mainthread_native_id = threading.main_thread().native_id
+        q.put(mainthread_native_id)
+
+    @classmethod
+    def _sleep_some(cls):
+        time.sleep(100)
+
+    @classmethod
+    def _test_sleep(cls, delay):
+        time.sleep(delay)
+
+    def _kill_process(self, meth):
+        if self.TYPE == 'threads':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        p = self.Process(target=self._sleep_some)
+        p.daemon = True
+        p.start()
+
+        self.assertEqual(p.is_alive(), True)
+        self.assertIn(p, self.active_children())
+        self.assertEqual(p.exitcode, None)
+
+        join = TimingWrapper(p.join)
+
+        self.assertEqual(join(0), None)
+        self.assertTimingAlmostEqual(join.elapsed, 0.0)
+        self.assertEqual(p.is_alive(), True)
+
+        self.assertEqual(join(-1), None)
+        self.assertTimingAlmostEqual(join.elapsed, 0.0)
+        self.assertEqual(p.is_alive(), True)
+
+        # XXX maybe terminating too soon causes the problems on Gentoo...
+        time.sleep(1)
+
+        meth(p)
+
+        if hasattr(signal, 'alarm'):
+            # On the Gentoo buildbot waitpid() often seems to block forever.
+            # We use alarm() to interrupt it if it blocks for too long.
+            def handler(*args):
+                raise RuntimeError('join took too long: %s' % p)
+            old_handler = signal.signal(signal.SIGALRM, handler)
+            try:
+                signal.alarm(10)
+                self.assertEqual(join(), None)
+            finally:
+                signal.alarm(0)
+                signal.signal(signal.SIGALRM, old_handler)
+        else:
+            self.assertEqual(join(), None)
+
+        self.assertTimingAlmostEqual(join.elapsed, 0.0)
+
+        self.assertEqual(p.is_alive(), False)
+        self.assertNotIn(p, self.active_children())
+
+        p.join()
+
+        return p.exitcode
+
+    def test_terminate(self):
+        exitcode = self._kill_process(multiprocessing.Process.terminate)
+        if os.name != 'nt':
+            self.assertEqual(exitcode, -signal.SIGTERM)
+
+    def test_kill(self):
+        exitcode = self._kill_process(multiprocessing.Process.kill)
+        if os.name != 'nt':
+            self.assertEqual(exitcode, -signal.SIGKILL)
+
+    def test_cpu_count(self):
+        try:
+            cpus = multiprocessing.cpu_count()
+        except NotImplementedError:
+            cpus = 1
+        self.assertTrue(type(cpus) is int)
+        self.assertTrue(cpus >= 1)
+
+    def test_active_children(self):
+        self.assertEqual(type(self.active_children()), list)
+
+        p = self.Process(target=time.sleep, args=(DELTA,))
+        self.assertNotIn(p, self.active_children())
+
+        p.daemon = True
+        p.start()
+        self.assertIn(p, self.active_children())
+
+        p.join()
+        self.assertNotIn(p, self.active_children())
+
+    @classmethod
+    def _test_recursion(cls, wconn, id):
+        wconn.send(id)
+        if len(id) < 2:
+            for i in range(2):
+                p = cls.Process(
+                    target=cls._test_recursion, args=(wconn, id+[i])
+                    )
+                p.start()
+                p.join()
+
+    @unittest.skipIf(True, "fails with is_dill(obj, child=True)")
+    def test_recursion(self):
+        rconn, wconn = self.Pipe(duplex=False)
+        self._test_recursion(wconn, [])
+
+        time.sleep(DELTA)
+        result = []
+        while rconn.poll():
+            result.append(rconn.recv())
+
+        expected = [
+            [],
+              [0],
+                [0, 0],
+                [0, 1],
+              [1],
+                [1, 0],
+                [1, 1]
+            ]
+        self.assertEqual(result, expected)
+
+    @classmethod
+    def _test_sentinel(cls, event):
+        event.wait(10.0)
+
+    def test_sentinel(self):
+        if self.TYPE == "threads":
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+        event = self.Event()
+        p = self.Process(target=self._test_sentinel, args=(event,))
+        with self.assertRaises(ValueError):
+            p.sentinel
+        p.start()
+        self.addCleanup(p.join)
+        sentinel = p.sentinel
+        self.assertIsInstance(sentinel, int)
+        self.assertFalse(wait_for_handle(sentinel, timeout=0.0))
+        event.set()
+        p.join()
+        self.assertTrue(wait_for_handle(sentinel, timeout=1))
+
+    @classmethod
+    def _test_close(cls, rc=0, q=None):
+        if q is not None:
+            q.get()
+        sys.exit(rc)
+
+    def test_close(self):
+        if self.TYPE == "threads":
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+        q = self.Queue()
+        p = self.Process(target=self._test_close, kwargs={'q': q})
+        p.daemon = True
+        p.start()
+        self.assertEqual(p.is_alive(), True)
+        # Child is still alive, cannot close
+        with self.assertRaises(ValueError):
+            p.close()
+
+        q.put(None)
+        p.join()
+        self.assertEqual(p.is_alive(), False)
+        self.assertEqual(p.exitcode, 0)
+        p.close()
+        with self.assertRaises(ValueError):
+            p.is_alive()
+        with self.assertRaises(ValueError):
+            p.join()
+        with self.assertRaises(ValueError):
+            p.terminate()
+        p.close()
+
+        wr = weakref.ref(p)
+        del p
+        gc.collect()
+        self.assertIs(wr(), None)
+
+        close_queue(q)
+
+    def test_many_processes(self):
+        if self.TYPE == 'threads':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        sm = multiprocessing.get_start_method()
+        travis = os.environ.get('COVERAGE') #XXX: travis-ci
+        N = (1 if travis else 5) if sm == 'spawn' else 100
+
+        # Try to overwhelm the forkserver loop with events
+        procs = [self.Process(target=self._test_sleep, args=(0.01,))
+                 for i in range(N)]
+        for p in procs:
+            p.start()
+        for p in procs:
+            join_process(p)
+        for p in procs:
+            self.assertEqual(p.exitcode, 0)
+
+        procs = [self.Process(target=self._sleep_some)
+                 for i in range(N)]
+        for p in procs:
+            p.start()
+        time.sleep(0.001)  # let the children start...
+        for p in procs:
+            p.terminate()
+        for p in procs:
+            join_process(p)
+        if os.name != 'nt':
+            exitcodes = [-signal.SIGTERM]
+            if sys.platform == 'darwin':
+                # bpo-31510: On macOS, killing a freshly started process with
+                # SIGTERM sometimes kills the process with SIGKILL.
+                exitcodes.append(-signal.SIGKILL)
+            for p in procs:
+                self.assertIn(p.exitcode, exitcodes)
+
+    def test_lose_target_ref(self):
+        c = DummyCallable()
+        wr = weakref.ref(c)
+        q = self.Queue()
+        p = self.Process(target=c, args=(q, c))
+        del c
+        p.start()
+        p.join()
+        gc.collect()  # For PyPy or other GCs.
+        self.assertIs(wr(), None)
+        self.assertEqual(q.get(), 5)
+        close_queue(q)
+
+    @classmethod
+    def _test_child_fd_inflation(self, evt, q):
+        q.put(os_helper.fd_count())
+        evt.wait()
+
+    def test_child_fd_inflation(self):
+        # Number of fds in child processes should not grow with the
+        # number of running children.
+        if self.TYPE == 'threads':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        sm = multiprocessing.get_start_method()
+        if sm == 'fork':
+            # The fork method by design inherits all fds from the parent,
+            # trying to go against it is a lost battle
+            self.skipTest('test not appropriate for {}'.format(sm))
+
+        N = 5
+        evt = self.Event()
+        q = self.Queue()
+
+        procs = [self.Process(target=self._test_child_fd_inflation, args=(evt, q))
+                 for i in range(N)]
+        for p in procs:
+            p.start()
+
+        try:
+            fd_counts = [q.get() for i in range(N)]
+            self.assertEqual(len(set(fd_counts)), 1, fd_counts)
+
+        finally:
+            evt.set()
+            for p in procs:
+                p.join()
+            close_queue(q)
+
+    @classmethod
+    def _test_wait_for_threads(self, evt):
+        def func1():
+            time.sleep(0.5)
+            evt.set()
+
+        def func2():
+            time.sleep(20)
+            evt.clear()
+
+        threading.Thread(target=func1).start()
+        threading.Thread(target=func2, daemon=True).start()
+
+    def test_wait_for_threads(self):
+        # A child process should wait for non-daemonic threads to end
+        # before exiting
+        if self.TYPE == 'threads':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        evt = self.Event()
+        proc = self.Process(target=self._test_wait_for_threads, args=(evt,))
+        proc.start()
+        proc.join()
+        self.assertTrue(evt.is_set())
+
+    @classmethod
+    def _test_error_on_stdio_flush(self, evt, break_std_streams={}):
+        for stream_name, action in break_std_streams.items():
+            if action == 'close':
+                stream = io.StringIO()
+                stream.close()
+            else:
+                assert action == 'remove'
+                stream = None
+            setattr(sys, stream_name, None)
+        evt.set()
+
+    def test_error_on_stdio_flush_1(self):
+        # Check that Process works with broken standard streams
+        streams = [io.StringIO(), None]
+        streams[0].close()
+        for stream_name in ('stdout', 'stderr'):
+            for stream in streams:
+                old_stream = getattr(sys, stream_name)
+                setattr(sys, stream_name, stream)
+                try:
+                    evt = self.Event()
+                    proc = self.Process(target=self._test_error_on_stdio_flush,
+                                        args=(evt,))
+                    proc.start()
+                    proc.join()
+                    self.assertTrue(evt.is_set())
+                    self.assertEqual(proc.exitcode, 0)
+                finally:
+                    setattr(sys, stream_name, old_stream)
+
+    def test_error_on_stdio_flush_2(self):
+        # Same as test_error_on_stdio_flush_1(), but standard streams are
+        # broken by the child process
+        for stream_name in ('stdout', 'stderr'):
+            for action in ('close', 'remove'):
+                old_stream = getattr(sys, stream_name)
+                try:
+                    evt = self.Event()
+                    proc = self.Process(target=self._test_error_on_stdio_flush,
+                                        args=(evt, {stream_name: action}))
+                    proc.start()
+                    proc.join()
+                    self.assertTrue(evt.is_set())
+                    self.assertEqual(proc.exitcode, 0)
+                finally:
+                    setattr(sys, stream_name, old_stream)
+
+    @classmethod
+    def _sleep_and_set_event(self, evt, delay=0.0):
+        time.sleep(delay)
+        evt.set()
+
+    def check_forkserver_death(self, signum):
+        # bpo-31308: if the forkserver process has died, we should still
+        # be able to create and run new Process instances (the forkserver
+        # is implicitly restarted).
+        if self.TYPE == 'threads':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+        sm = multiprocessing.get_start_method()
+        if sm != 'forkserver':
+            # The fork method by design inherits all fds from the parent,
+            # trying to go against it is a lost battle
+            self.skipTest('test not appropriate for {}'.format(sm))
+
+        from multiprocess.forkserver import _forkserver
+        _forkserver.ensure_running()
+
+        # First process sleeps 500 ms
+        delay = 0.5
+
+        evt = self.Event()
+        proc = self.Process(target=self._sleep_and_set_event, args=(evt, delay))
+        proc.start()
+
+        pid = _forkserver._forkserver_pid
+        os.kill(pid, signum)
+        # give time to the fork server to die and time to proc to complete
+        time.sleep(delay * 2.0)
+
+        evt2 = self.Event()
+        proc2 = self.Process(target=self._sleep_and_set_event, args=(evt2,))
+        proc2.start()
+        proc2.join()
+        self.assertTrue(evt2.is_set())
+        self.assertEqual(proc2.exitcode, 0)
+
+        proc.join()
+        self.assertTrue(evt.is_set())
+        self.assertIn(proc.exitcode, (0, 255))
+
+    def test_forkserver_sigint(self):
+        # Catchable signal
+        self.check_forkserver_death(signal.SIGINT)
+
+    def test_forkserver_sigkill(self):
+        # Uncatchable signal
+        if os.name != 'nt':
+            self.check_forkserver_death(signal.SIGKILL)
+
+
+#
+#
+#
+
+class _UpperCaser(multiprocessing.Process):
+
+    def __init__(self):
+        multiprocessing.Process.__init__(self)
+        self.child_conn, self.parent_conn = multiprocessing.Pipe()
+
+    def run(self):
+        self.parent_conn.close()
+        for s in iter(self.child_conn.recv, None):
+            self.child_conn.send(s.upper())
+        self.child_conn.close()
+
+    def submit(self, s):
+        assert type(s) is str
+        self.parent_conn.send(s)
+        return self.parent_conn.recv()
+
+    def stop(self):
+        self.parent_conn.send(None)
+        self.parent_conn.close()
+        self.child_conn.close()
+
+class _TestSubclassingProcess(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes',)
+
+    def test_subclassing(self):
+        uppercaser = _UpperCaser()
+        uppercaser.daemon = True
+        uppercaser.start()
+        self.assertEqual(uppercaser.submit('hello'), 'HELLO')
+        self.assertEqual(uppercaser.submit('world'), 'WORLD')
+        uppercaser.stop()
+        uppercaser.join()
+
+    def test_stderr_flush(self):
+        # sys.stderr is flushed at process shutdown (issue #13812)
+        if self.TYPE == "threads":
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        testfn = os_helper.TESTFN
+        self.addCleanup(os_helper.unlink, testfn)
+        proc = self.Process(target=self._test_stderr_flush, args=(testfn,))
+        proc.start()
+        proc.join()
+        with open(testfn, encoding="utf-8") as f:
+            err = f.read()
+            # The whole traceback was printed
+            self.assertIn("ZeroDivisionError", err)
+            self.assertIn("__init__.py", err)
+            #self.assertIn("1/0 # MARKER", err) #FIXME
+
+    @classmethod
+    def _test_stderr_flush(cls, testfn):
+        fd = os.open(testfn, os.O_WRONLY | os.O_CREAT | os.O_EXCL)
+        sys.stderr = open(fd, 'w', encoding="utf-8", closefd=False)
+        1/0 # MARKER
+
+
+    @classmethod
+    def _test_sys_exit(cls, reason, testfn):
+        fd = os.open(testfn, os.O_WRONLY | os.O_CREAT | os.O_EXCL)
+        sys.stderr = open(fd, 'w', encoding="utf-8", closefd=False)
+        sys.exit(reason)
+
+    def test_sys_exit(self):
+        # See Issue 13854
+        if self.TYPE == 'threads':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        testfn = os_helper.TESTFN
+        self.addCleanup(os_helper.unlink, testfn)
+
+        for reason in (
+            [1, 2, 3],
+            'ignore this',
+        ):
+            p = self.Process(target=self._test_sys_exit, args=(reason, testfn))
+            p.daemon = True
+            p.start()
+            join_process(p)
+            self.assertEqual(p.exitcode, 1)
+
+            with open(testfn, encoding="utf-8") as f:
+                content = f.read()
+            self.assertEqual(content.rstrip(), str(reason))
+
+            os.unlink(testfn)
+
+        cases = [
+            ((True,), 1),
+            ((False,), 0),
+            ((8,), 8),
+            ((None,), 0),
+            ((), 0),
+            ]
+
+        for args, expected in cases:
+            with self.subTest(args=args):
+                p = self.Process(target=sys.exit, args=args)
+                p.daemon = True
+                p.start()
+                join_process(p)
+                self.assertEqual(p.exitcode, expected)
+
+#
+#
+#
+
+def queue_empty(q):
+    if hasattr(q, 'empty'):
+        return q.empty()
+    else:
+        return q.qsize() == 0
+
+def queue_full(q, maxsize):
+    if hasattr(q, 'full'):
+        return q.full()
+    else:
+        return q.qsize() == maxsize
+
+
+class _TestQueue(BaseTestCase):
+
+
+    @classmethod
+    def _test_put(cls, queue, child_can_start, parent_can_continue):
+        child_can_start.wait()
+        for i in range(6):
+            queue.get()
+        parent_can_continue.set()
+
+    def test_put(self):
+        MAXSIZE = 6
+        queue = self.Queue(maxsize=MAXSIZE)
+        child_can_start = self.Event()
+        parent_can_continue = self.Event()
+
+        proc = self.Process(
+            target=self._test_put,
+            args=(queue, child_can_start, parent_can_continue)
+            )
+        proc.daemon = True
+        proc.start()
+
+        self.assertEqual(queue_empty(queue), True)
+        self.assertEqual(queue_full(queue, MAXSIZE), False)
+
+        queue.put(1)
+        queue.put(2, True)
+        queue.put(3, True, None)
+        queue.put(4, False)
+        queue.put(5, False, None)
+        queue.put_nowait(6)
+
+        # the values may be in buffer but not yet in pipe so sleep a bit
+        time.sleep(DELTA)
+
+        self.assertEqual(queue_empty(queue), False)
+        self.assertEqual(queue_full(queue, MAXSIZE), True)
+
+        put = TimingWrapper(queue.put)
+        put_nowait = TimingWrapper(queue.put_nowait)
+
+        self.assertRaises(pyqueue.Full, put, 7, False)
+        self.assertTimingAlmostEqual(put.elapsed, 0)
+
+        self.assertRaises(pyqueue.Full, put, 7, False, None)
+        self.assertTimingAlmostEqual(put.elapsed, 0)
+
+        self.assertRaises(pyqueue.Full, put_nowait, 7)
+        self.assertTimingAlmostEqual(put_nowait.elapsed, 0)
+
+        self.assertRaises(pyqueue.Full, put, 7, True, TIMEOUT1)
+        self.assertTimingAlmostEqual(put.elapsed, TIMEOUT1)
+
+        self.assertRaises(pyqueue.Full, put, 7, False, TIMEOUT2)
+        self.assertTimingAlmostEqual(put.elapsed, 0)
+
+        self.assertRaises(pyqueue.Full, put, 7, True, timeout=TIMEOUT3)
+        self.assertTimingAlmostEqual(put.elapsed, TIMEOUT3)
+
+        child_can_start.set()
+        parent_can_continue.wait()
+
+        self.assertEqual(queue_empty(queue), True)
+        self.assertEqual(queue_full(queue, MAXSIZE), False)
+
+        proc.join()
+        close_queue(queue)
+
+    @classmethod
+    def _test_get(cls, queue, child_can_start, parent_can_continue):
+        child_can_start.wait()
+        #queue.put(1)
+        queue.put(2)
+        queue.put(3)
+        queue.put(4)
+        queue.put(5)
+        parent_can_continue.set()
+
+    def test_get(self):
+        queue = self.Queue()
+        child_can_start = self.Event()
+        parent_can_continue = self.Event()
+
+        proc = self.Process(
+            target=self._test_get,
+            args=(queue, child_can_start, parent_can_continue)
+            )
+        proc.daemon = True
+        proc.start()
+
+        self.assertEqual(queue_empty(queue), True)
+
+        child_can_start.set()
+        parent_can_continue.wait()
+
+        time.sleep(DELTA)
+        self.assertEqual(queue_empty(queue), False)
+
+        # Hangs unexpectedly, remove for now
+        #self.assertEqual(queue.get(), 1)
+        self.assertEqual(queue.get(True, None), 2)
+        self.assertEqual(queue.get(True), 3)
+        self.assertEqual(queue.get(timeout=1), 4)
+        self.assertEqual(queue.get_nowait(), 5)
+
+        self.assertEqual(queue_empty(queue), True)
+
+        get = TimingWrapper(queue.get)
+        get_nowait = TimingWrapper(queue.get_nowait)
+
+        self.assertRaises(pyqueue.Empty, get, False)
+        self.assertTimingAlmostEqual(get.elapsed, 0)
+
+        self.assertRaises(pyqueue.Empty, get, False, None)
+        self.assertTimingAlmostEqual(get.elapsed, 0)
+
+        self.assertRaises(pyqueue.Empty, get_nowait)
+        self.assertTimingAlmostEqual(get_nowait.elapsed, 0)
+
+        self.assertRaises(pyqueue.Empty, get, True, TIMEOUT1)
+        self.assertTimingAlmostEqual(get.elapsed, TIMEOUT1)
+
+        self.assertRaises(pyqueue.Empty, get, False, TIMEOUT2)
+        self.assertTimingAlmostEqual(get.elapsed, 0)
+
+        self.assertRaises(pyqueue.Empty, get, timeout=TIMEOUT3)
+        self.assertTimingAlmostEqual(get.elapsed, TIMEOUT3)
+
+        proc.join()
+        close_queue(queue)
+
+    @classmethod
+    def _test_fork(cls, queue):
+        for i in range(10, 20):
+            queue.put(i)
+        # note that at this point the items may only be buffered, so the
+        # process cannot shutdown until the feeder thread has finished
+        # pushing items onto the pipe.
+
+    def test_fork(self):
+        # Old versions of Queue would fail to create a new feeder
+        # thread for a forked process if the original process had its
+        # own feeder thread.  This test checks that this no longer
+        # happens.
+
+        queue = self.Queue()
+
+        # put items on queue so that main process starts a feeder thread
+        for i in range(10):
+            queue.put(i)
+
+        # wait to make sure thread starts before we fork a new process
+        time.sleep(DELTA)
+
+        # fork process
+        p = self.Process(target=self._test_fork, args=(queue,))
+        p.daemon = True
+        p.start()
+
+        # check that all expected items are in the queue
+        for i in range(20):
+            self.assertEqual(queue.get(), i)
+        self.assertRaises(pyqueue.Empty, queue.get, False)
+
+        p.join()
+        close_queue(queue)
+
+    def test_qsize(self):
+        q = self.Queue()
+        try:
+            self.assertEqual(q.qsize(), 0)
+        except NotImplementedError:
+            self.skipTest('qsize method not implemented')
+        q.put(1)
+        self.assertEqual(q.qsize(), 1)
+        q.put(5)
+        self.assertEqual(q.qsize(), 2)
+        q.get()
+        self.assertEqual(q.qsize(), 1)
+        q.get()
+        self.assertEqual(q.qsize(), 0)
+        close_queue(q)
+
+    @classmethod
+    def _test_task_done(cls, q):
+        for obj in iter(q.get, None):
+            time.sleep(DELTA)
+            q.task_done()
+
+    def test_task_done(self):
+        queue = self.JoinableQueue()
+
+        workers = [self.Process(target=self._test_task_done, args=(queue,))
+                   for i in range(4)]
+
+        for p in workers:
+            p.daemon = True
+            p.start()
+
+        for i in range(10):
+            queue.put(i)
+
+        queue.join()
+
+        for p in workers:
+            queue.put(None)
+
+        for p in workers:
+            p.join()
+        close_queue(queue)
+
+    def test_no_import_lock_contention(self):
+        with os_helper.temp_cwd():
+            module_name = 'imported_by_an_imported_module'
+            with open(module_name + '.py', 'w', encoding="utf-8") as f:
+                f.write("""if 1:
+                    import multiprocess as multiprocessing
+
+                    q = multiprocessing.Queue()
+                    q.put('knock knock')
+                    q.get(timeout=3)
+                    q.close()
+                    del q
+                """)
+
+            with import_helper.DirsOnSysPath(os.getcwd()):
+                try:
+                    __import__(module_name)
+                except pyqueue.Empty:
+                    self.fail("Probable regression on import lock contention;"
+                              " see Issue #22853")
+
+    def test_timeout(self):
+        q = multiprocessing.Queue()
+        start = time.monotonic()
+        self.assertRaises(pyqueue.Empty, q.get, True, 0.200)
+        delta = time.monotonic() - start
+        # bpo-30317: Tolerate a delta of 100 ms because of the bad clock
+        # resolution on Windows (usually 15.6 ms). x86 Windows7 3.x once
+        # failed because the delta was only 135.8 ms.
+        self.assertGreaterEqual(delta, 0.100)
+        close_queue(q)
+
+    def test_queue_feeder_donot_stop_onexc(self):
+        # bpo-30414: verify feeder handles exceptions correctly
+        if self.TYPE != 'processes':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        class NotSerializable(object):
+            def __reduce__(self):
+                raise AttributeError
+        with test.support.captured_stderr():
+            q = self.Queue()
+            q.put(NotSerializable())
+            q.put(True)
+            self.assertTrue(q.get(timeout=support.SHORT_TIMEOUT))
+            close_queue(q)
+
+        with test.support.captured_stderr():
+            # bpo-33078: verify that the queue size is correctly handled
+            # on errors.
+            q = self.Queue(maxsize=1)
+            q.put(NotSerializable())
+            q.put(True)
+            try:
+                self.assertEqual(q.qsize(), 1)
+            except NotImplementedError:
+                # qsize is not available on all platform as it
+                # relies on sem_getvalue
+                pass
+            self.assertTrue(q.get(timeout=support.SHORT_TIMEOUT))
+            # Check that the size of the queue is correct
+            self.assertTrue(q.empty())
+            close_queue(q)
+
+    def test_queue_feeder_on_queue_feeder_error(self):
+        # bpo-30006: verify feeder handles exceptions using the
+        # _on_queue_feeder_error hook.
+        if self.TYPE != 'processes':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        class NotSerializable(object):
+            """Mock unserializable object"""
+            def __init__(self):
+                self.reduce_was_called = False
+                self.on_queue_feeder_error_was_called = False
+
+            def __reduce__(self):
+                self.reduce_was_called = True
+                raise AttributeError
+
+        class SafeQueue(multiprocessing.queues.Queue):
+            """Queue with overloaded _on_queue_feeder_error hook"""
+            @staticmethod
+            def _on_queue_feeder_error(e, obj):
+                if (isinstance(e, AttributeError) and
+                        isinstance(obj, NotSerializable)):
+                    obj.on_queue_feeder_error_was_called = True
+
+        not_serializable_obj = NotSerializable()
+        # The captured_stderr reduces the noise in the test report
+        with test.support.captured_stderr():
+            q = SafeQueue(ctx=multiprocessing.get_context())
+            q.put(not_serializable_obj)
+
+            # Verify that q is still functioning correctly
+            q.put(True)
+            self.assertTrue(q.get(timeout=support.SHORT_TIMEOUT))
+
+        # Assert that the serialization and the hook have been called correctly
+        self.assertTrue(not_serializable_obj.reduce_was_called)
+        self.assertTrue(not_serializable_obj.on_queue_feeder_error_was_called)
+
+    def test_closed_queue_put_get_exceptions(self):
+        for q in multiprocessing.Queue(), multiprocessing.JoinableQueue():
+            q.close()
+            with self.assertRaisesRegex(ValueError, 'is closed'):
+                q.put('foo')
+            with self.assertRaisesRegex(ValueError, 'is closed'):
+                q.get()
+#
+#
+#
+
+class _TestLock(BaseTestCase):
+
+    def test_lock(self):
+        lock = self.Lock()
+        self.assertEqual(lock.acquire(), True)
+        self.assertEqual(lock.acquire(False), False)
+        self.assertEqual(lock.release(), None)
+        self.assertRaises((ValueError, threading.ThreadError), lock.release)
+
+    def test_rlock(self):
+        lock = self.RLock()
+        self.assertEqual(lock.acquire(), True)
+        self.assertEqual(lock.acquire(), True)
+        self.assertEqual(lock.acquire(), True)
+        self.assertEqual(lock.release(), None)
+        self.assertEqual(lock.release(), None)
+        self.assertEqual(lock.release(), None)
+        self.assertRaises((AssertionError, RuntimeError), lock.release)
+
+    def test_lock_context(self):
+        with self.Lock():
+            pass
+
+
+class _TestSemaphore(BaseTestCase):
+
+    def _test_semaphore(self, sem):
+        self.assertReturnsIfImplemented(2, get_value, sem)
+        self.assertEqual(sem.acquire(), True)
+        self.assertReturnsIfImplemented(1, get_value, sem)
+        self.assertEqual(sem.acquire(), True)
+        self.assertReturnsIfImplemented(0, get_value, sem)
+        self.assertEqual(sem.acquire(False), False)
+        self.assertReturnsIfImplemented(0, get_value, sem)
+        self.assertEqual(sem.release(), None)
+        self.assertReturnsIfImplemented(1, get_value, sem)
+        self.assertEqual(sem.release(), None)
+        self.assertReturnsIfImplemented(2, get_value, sem)
+
+    def test_semaphore(self):
+        sem = self.Semaphore(2)
+        self._test_semaphore(sem)
+        self.assertEqual(sem.release(), None)
+        self.assertReturnsIfImplemented(3, get_value, sem)
+        self.assertEqual(sem.release(), None)
+        self.assertReturnsIfImplemented(4, get_value, sem)
+
+    def test_bounded_semaphore(self):
+        sem = self.BoundedSemaphore(2)
+        self._test_semaphore(sem)
+        # Currently fails on OS/X
+        #if HAVE_GETVALUE:
+        #    self.assertRaises(ValueError, sem.release)
+        #    self.assertReturnsIfImplemented(2, get_value, sem)
+
+    def test_timeout(self):
+        if self.TYPE != 'processes':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        sem = self.Semaphore(0)
+        acquire = TimingWrapper(sem.acquire)
+
+        self.assertEqual(acquire(False), False)
+        self.assertTimingAlmostEqual(acquire.elapsed, 0.0)
+
+        self.assertEqual(acquire(False, None), False)
+        self.assertTimingAlmostEqual(acquire.elapsed, 0.0)
+
+        self.assertEqual(acquire(False, TIMEOUT1), False)
+        self.assertTimingAlmostEqual(acquire.elapsed, 0)
+
+        self.assertEqual(acquire(True, TIMEOUT2), False)
+        self.assertTimingAlmostEqual(acquire.elapsed, TIMEOUT2)
+
+        self.assertEqual(acquire(timeout=TIMEOUT3), False)
+        self.assertTimingAlmostEqual(acquire.elapsed, TIMEOUT3)
+
+
+class _TestCondition(BaseTestCase):
+
+    @classmethod
+    def f(cls, cond, sleeping, woken, timeout=None):
+        cond.acquire()
+        sleeping.release()
+        cond.wait(timeout)
+        woken.release()
+        cond.release()
+
+    def assertReachesEventually(self, func, value):
+        for i in range(10):
+            try:
+                if func() == value:
+                    break
+            except NotImplementedError:
+                break
+            time.sleep(DELTA)
+        time.sleep(DELTA)
+        self.assertReturnsIfImplemented(value, func)
+
+    def check_invariant(self, cond):
+        # this is only supposed to succeed when there are no sleepers
+        if self.TYPE == 'processes':
+            try:
+                sleepers = (cond._sleeping_count.get_value() -
+                            cond._woken_count.get_value())
+                self.assertEqual(sleepers, 0)
+                self.assertEqual(cond._wait_semaphore.get_value(), 0)
+            except NotImplementedError:
+                pass
+
+    def test_notify(self):
+        cond = self.Condition()
+        sleeping = self.Semaphore(0)
+        woken = self.Semaphore(0)
+
+        p = self.Process(target=self.f, args=(cond, sleeping, woken))
+        p.daemon = True
+        p.start()
+        self.addCleanup(p.join)
+
+        p = threading.Thread(target=self.f, args=(cond, sleeping, woken))
+        p.daemon = True
+        p.start()
+        self.addCleanup(p.join)
+
+        # wait for both children to start sleeping
+        sleeping.acquire()
+        sleeping.acquire()
+
+        # check no process/thread has woken up
+        time.sleep(DELTA)
+        self.assertReturnsIfImplemented(0, get_value, woken)
+
+        # wake up one process/thread
+        cond.acquire()
+        cond.notify()
+        cond.release()
+
+        # check one process/thread has woken up
+        time.sleep(DELTA)
+        self.assertReturnsIfImplemented(1, get_value, woken)
+
+        # wake up another
+        cond.acquire()
+        cond.notify()
+        cond.release()
+
+        # check other has woken up
+        time.sleep(DELTA)
+        self.assertReturnsIfImplemented(2, get_value, woken)
+
+        # check state is not mucked up
+        self.check_invariant(cond)
+        p.join()
+
+    def test_notify_all(self):
+        cond = self.Condition()
+        sleeping = self.Semaphore(0)
+        woken = self.Semaphore(0)
+
+        # start some threads/processes which will timeout
+        for i in range(3):
+            p = self.Process(target=self.f,
+                             args=(cond, sleeping, woken, TIMEOUT1))
+            p.daemon = True
+            p.start()
+            self.addCleanup(p.join)
+
+            t = threading.Thread(target=self.f,
+                                 args=(cond, sleeping, woken, TIMEOUT1))
+            t.daemon = True
+            t.start()
+            self.addCleanup(t.join)
+
+        # wait for them all to sleep
+        for i in range(6):
+            sleeping.acquire()
+
+        # check they have all timed out
+        for i in range(6):
+            woken.acquire()
+        self.assertReturnsIfImplemented(0, get_value, woken)
+
+        # check state is not mucked up
+        self.check_invariant(cond)
+
+        # start some more threads/processes
+        for i in range(3):
+            p = self.Process(target=self.f, args=(cond, sleeping, woken))
+            p.daemon = True
+            p.start()
+            self.addCleanup(p.join)
+
+            t = threading.Thread(target=self.f, args=(cond, sleeping, woken))
+            t.daemon = True
+            t.start()
+            self.addCleanup(t.join)
+
+        # wait for them to all sleep
+        for i in range(6):
+            sleeping.acquire()
+
+        # check no process/thread has woken up
+        time.sleep(DELTA)
+        self.assertReturnsIfImplemented(0, get_value, woken)
+
+        # wake them all up
+        cond.acquire()
+        cond.notify_all()
+        cond.release()
+
+        # check they have all woken
+        self.assertReachesEventually(lambda: get_value(woken), 6)
+
+        # check state is not mucked up
+        self.check_invariant(cond)
+
+    def test_notify_n(self):
+        cond = self.Condition()
+        sleeping = self.Semaphore(0)
+        woken = self.Semaphore(0)
+
+        # start some threads/processes
+        for i in range(3):
+            p = self.Process(target=self.f, args=(cond, sleeping, woken))
+            p.daemon = True
+            p.start()
+            self.addCleanup(p.join)
+
+            t = threading.Thread(target=self.f, args=(cond, sleeping, woken))
+            t.daemon = True
+            t.start()
+            self.addCleanup(t.join)
+
+        # wait for them to all sleep
+        for i in range(6):
+            sleeping.acquire()
+
+        # check no process/thread has woken up
+        time.sleep(DELTA)
+        self.assertReturnsIfImplemented(0, get_value, woken)
+
+        # wake some of them up
+        cond.acquire()
+        cond.notify(n=2)
+        cond.release()
+
+        # check 2 have woken
+        self.assertReachesEventually(lambda: get_value(woken), 2)
+
+        # wake the rest of them
+        cond.acquire()
+        cond.notify(n=4)
+        cond.release()
+
+        self.assertReachesEventually(lambda: get_value(woken), 6)
+
+        # doesn't do anything more
+        cond.acquire()
+        cond.notify(n=3)
+        cond.release()
+
+        self.assertReturnsIfImplemented(6, get_value, woken)
+
+        # check state is not mucked up
+        self.check_invariant(cond)
+
+    def test_timeout(self):
+        cond = self.Condition()
+        wait = TimingWrapper(cond.wait)
+        cond.acquire()
+        res = wait(TIMEOUT1)
+        cond.release()
+        self.assertEqual(res, False)
+        self.assertTimingAlmostEqual(wait.elapsed, TIMEOUT1)
+
+    @classmethod
+    def _test_waitfor_f(cls, cond, state):
+        with cond:
+            state.value = 0
+            cond.notify()
+            result = cond.wait_for(lambda : state.value==4)
+            if not result or state.value != 4:
+                sys.exit(1)
+
+    @unittest.skipUnless(HAS_SHAREDCTYPES, 'needs sharedctypes')
+    def test_waitfor(self):
+        # based on test in test/lock_tests.py
+        cond = self.Condition()
+        state = self.Value('i', -1)
+
+        p = self.Process(target=self._test_waitfor_f, args=(cond, state))
+        p.daemon = True
+        p.start()
+
+        with cond:
+            result = cond.wait_for(lambda : state.value==0)
+            self.assertTrue(result)
+            self.assertEqual(state.value, 0)
+
+        for i in range(4):
+            time.sleep(0.01)
+            with cond:
+                state.value += 1
+                cond.notify()
+
+        join_process(p)
+        self.assertEqual(p.exitcode, 0)
+
+    @classmethod
+    def _test_waitfor_timeout_f(cls, cond, state, success, sem):
+        sem.release()
+        with cond:
+            expected = 0.1
+            dt = time.monotonic()
+            result = cond.wait_for(lambda : state.value==4, timeout=expected)
+            dt = time.monotonic() - dt
+            # borrow logic in assertTimeout() from test/lock_tests.py
+            if not result and expected * 0.6 < dt < expected * 10.0:
+                success.value = True
+
+    @unittest.skipUnless(HAS_SHAREDCTYPES, 'needs sharedctypes')
+    def test_waitfor_timeout(self):
+        # based on test in test/lock_tests.py
+        cond = self.Condition()
+        state = self.Value('i', 0)
+        success = self.Value('i', False)
+        sem = self.Semaphore(0)
+
+        p = self.Process(target=self._test_waitfor_timeout_f,
+                         args=(cond, state, success, sem))
+        p.daemon = True
+        p.start()
+        self.assertTrue(sem.acquire(timeout=support.LONG_TIMEOUT))
+
+        # Only increment 3 times, so state == 4 is never reached.
+        for i in range(3):
+            time.sleep(0.01)
+            with cond:
+                state.value += 1
+                cond.notify()
+
+        join_process(p)
+        self.assertTrue(success.value)
+
+    @classmethod
+    def _test_wait_result(cls, c, pid):
+        with c:
+            c.notify()
+        time.sleep(1)
+        if pid is not None:
+            os.kill(pid, signal.SIGINT)
+
+    def test_wait_result(self):
+        if isinstance(self, ProcessesMixin) and sys.platform != 'win32':
+            pid = os.getpid()
+        else:
+            pid = None
+
+        c = self.Condition()
+        with c:
+            self.assertFalse(c.wait(0))
+            self.assertFalse(c.wait(0.1))
+
+            p = self.Process(target=self._test_wait_result, args=(c, pid))
+            p.start()
+
+            self.assertTrue(c.wait(60))
+            if pid is not None:
+                self.assertRaises(KeyboardInterrupt, c.wait, 60)
+
+            p.join()
+
+
+class _TestEvent(BaseTestCase):
+
+    @classmethod
+    def _test_event(cls, event):
+        time.sleep(TIMEOUT2)
+        event.set()
+
+    def test_event(self):
+        event = self.Event()
+        wait = TimingWrapper(event.wait)
+
+        # Removed temporarily, due to API shear, this does not
+        # work with threading._Event objects. is_set == isSet
+        self.assertEqual(event.is_set(), False)
+
+        # Removed, threading.Event.wait() will return the value of the __flag
+        # instead of None. API Shear with the semaphore backed mp.Event
+        self.assertEqual(wait(0.0), False)
+        self.assertTimingAlmostEqual(wait.elapsed, 0.0)
+        self.assertEqual(wait(TIMEOUT1), False)
+        self.assertTimingAlmostEqual(wait.elapsed, TIMEOUT1)
+
+        event.set()
+
+        # See note above on the API differences
+        self.assertEqual(event.is_set(), True)
+        self.assertEqual(wait(), True)
+        self.assertTimingAlmostEqual(wait.elapsed, 0.0)
+        self.assertEqual(wait(TIMEOUT1), True)
+        self.assertTimingAlmostEqual(wait.elapsed, 0.0)
+        # self.assertEqual(event.is_set(), True)
+
+        event.clear()
+
+        #self.assertEqual(event.is_set(), False)
+
+        p = self.Process(target=self._test_event, args=(event,))
+        p.daemon = True
+        p.start()
+        self.assertEqual(wait(), True)
+        p.join()
+
+#
+# Tests for Barrier - adapted from tests in test/lock_tests.py
+#
+
+# Many of the tests for threading.Barrier use a list as an atomic
+# counter: a value is appended to increment the counter, and the
+# length of the list gives the value.  We use the class DummyList
+# for the same purpose.
+
+class _DummyList(object):
+
+    def __init__(self):
+        wrapper = multiprocessing.heap.BufferWrapper(struct.calcsize('i'))
+        lock = multiprocessing.Lock()
+        self.__setstate__((wrapper, lock))
+        self._lengthbuf[0] = 0
+
+    def __setstate__(self, state):
+        (self._wrapper, self._lock) = state
+        self._lengthbuf = self._wrapper.create_memoryview().cast('i')
+
+    def __getstate__(self):
+        return (self._wrapper, self._lock)
+
+    def append(self, _):
+        with self._lock:
+            self._lengthbuf[0] += 1
+
+    def __len__(self):
+        with self._lock:
+            return self._lengthbuf[0]
+
+def _wait():
+    # A crude wait/yield function not relying on synchronization primitives.
+    time.sleep(0.01)
+
+
+class Bunch(object):
+    """
+    A bunch of threads.
+    """
+    def __init__(self, namespace, f, args, n, wait_before_exit=False):
+        """
+        Construct a bunch of `n` threads running the same function `f`.
+        If `wait_before_exit` is True, the threads won't terminate until
+        do_finish() is called.
+        """
+        self.f = f
+        self.args = args
+        self.n = n
+        self.started = namespace.DummyList()
+        self.finished = namespace.DummyList()
+        self._can_exit = namespace.Event()
+        if not wait_before_exit:
+            self._can_exit.set()
+
+        threads = []
+        for i in range(n):
+            p = namespace.Process(target=self.task)
+            p.daemon = True
+            p.start()
+            threads.append(p)
+
+        def finalize(threads):
+            for p in threads:
+                p.join()
+
+        self._finalizer = weakref.finalize(self, finalize, threads)
+
+    def task(self):
+        pid = os.getpid()
+        self.started.append(pid)
+        try:
+            self.f(*self.args)
+        finally:
+            self.finished.append(pid)
+            self._can_exit.wait(30)
+            assert self._can_exit.is_set()
+
+    def wait_for_started(self):
+        while len(self.started) < self.n:
+            _wait()
+
+    def wait_for_finished(self):
+        while len(self.finished) < self.n:
+            _wait()
+
+    def do_finish(self):
+        self._can_exit.set()
+
+    def close(self):
+        self._finalizer()
+
+
+class AppendTrue(object):
+    def __init__(self, obj):
+        self.obj = obj
+    def __call__(self):
+        self.obj.append(True)
+
+
+class _TestBarrier(BaseTestCase):
+    """
+    Tests for Barrier objects.
+    """
+    N = 5
+    defaultTimeout = 30.0  # XXX Slow Windows buildbots need generous timeout
+
+    def setUp(self):
+        self.barrier = self.Barrier(self.N, timeout=self.defaultTimeout)
+
+    def tearDown(self):
+        self.barrier.abort()
+        self.barrier = None
+
+    def DummyList(self):
+        if self.TYPE == 'threads':
+            return []
+        elif self.TYPE == 'manager':
+            return self.manager.list()
+        else:
+            return _DummyList()
+
+    def run_threads(self, f, args):
+        b = Bunch(self, f, args, self.N-1)
+        try:
+            f(*args)
+            b.wait_for_finished()
+        finally:
+            b.close()
+
+    @classmethod
+    def multipass(cls, barrier, results, n):
+        m = barrier.parties
+        assert m == cls.N
+        for i in range(n):
+            results[0].append(True)
+            assert len(results[1]) == i * m
+            barrier.wait()
+            results[1].append(True)
+            assert len(results[0]) == (i + 1) * m
+            barrier.wait()
+        try:
+            assert barrier.n_waiting == 0
+        except NotImplementedError:
+            pass
+        assert not barrier.broken
+
+    def test_barrier(self, passes=1):
+        """
+        Test that a barrier is passed in lockstep
+        """
+        results = [self.DummyList(), self.DummyList()]
+        self.run_threads(self.multipass, (self.barrier, results, passes))
+
+    def test_barrier_10(self):
+        """
+        Test that a barrier works for 10 consecutive runs
+        """
+        return self.test_barrier(10)
+
+    @classmethod
+    def _test_wait_return_f(cls, barrier, queue):
+        res = barrier.wait()
+        queue.put(res)
+
+    def test_wait_return(self):
+        """
+        test the return value from barrier.wait
+        """
+        queue = self.Queue()
+        self.run_threads(self._test_wait_return_f, (self.barrier, queue))
+        results = [queue.get() for i in range(self.N)]
+        self.assertEqual(results.count(0), 1)
+        close_queue(queue)
+
+    @classmethod
+    def _test_action_f(cls, barrier, results):
+        barrier.wait()
+        if len(results) != 1:
+            raise RuntimeError
+
+    def test_action(self):
+        """
+        Test the 'action' callback
+        """
+        results = self.DummyList()
+        barrier = self.Barrier(self.N, action=AppendTrue(results))
+        self.run_threads(self._test_action_f, (barrier, results))
+        self.assertEqual(len(results), 1)
+
+    @classmethod
+    def _test_abort_f(cls, barrier, results1, results2):
+        try:
+            i = barrier.wait()
+            if i == cls.N//2:
+                raise RuntimeError
+            barrier.wait()
+            results1.append(True)
+        except threading.BrokenBarrierError:
+            results2.append(True)
+        except RuntimeError:
+            barrier.abort()
+
+    def test_abort(self):
+        """
+        Test that an abort will put the barrier in a broken state
+        """
+        results1 = self.DummyList()
+        results2 = self.DummyList()
+        self.run_threads(self._test_abort_f,
+                         (self.barrier, results1, results2))
+        self.assertEqual(len(results1), 0)
+        self.assertEqual(len(results2), self.N-1)
+        self.assertTrue(self.barrier.broken)
+
+    @classmethod
+    def _test_reset_f(cls, barrier, results1, results2, results3):
+        i = barrier.wait()
+        if i == cls.N//2:
+            # Wait until the other threads are all in the barrier.
+            while barrier.n_waiting < cls.N-1:
+                time.sleep(0.001)
+            barrier.reset()
+        else:
+            try:
+                barrier.wait()
+                results1.append(True)
+            except threading.BrokenBarrierError:
+                results2.append(True)
+        # Now, pass the barrier again
+        barrier.wait()
+        results3.append(True)
+
+    def test_reset(self):
+        """
+        Test that a 'reset' on a barrier frees the waiting threads
+        """
+        results1 = self.DummyList()
+        results2 = self.DummyList()
+        results3 = self.DummyList()
+        self.run_threads(self._test_reset_f,
+                         (self.barrier, results1, results2, results3))
+        self.assertEqual(len(results1), 0)
+        self.assertEqual(len(results2), self.N-1)
+        self.assertEqual(len(results3), self.N)
+
+    @classmethod
+    def _test_abort_and_reset_f(cls, barrier, barrier2,
+                                results1, results2, results3):
+        try:
+            i = barrier.wait()
+            if i == cls.N//2:
+                raise RuntimeError
+            barrier.wait()
+            results1.append(True)
+        except threading.BrokenBarrierError:
+            results2.append(True)
+        except RuntimeError:
+            barrier.abort()
+        # Synchronize and reset the barrier.  Must synchronize first so
+        # that everyone has left it when we reset, and after so that no
+        # one enters it before the reset.
+        if barrier2.wait() == cls.N//2:
+            barrier.reset()
+        barrier2.wait()
+        barrier.wait()
+        results3.append(True)
+
+    def test_abort_and_reset(self):
+        """
+        Test that a barrier can be reset after being broken.
+        """
+        results1 = self.DummyList()
+        results2 = self.DummyList()
+        results3 = self.DummyList()
+        barrier2 = self.Barrier(self.N)
+
+        self.run_threads(self._test_abort_and_reset_f,
+                         (self.barrier, barrier2, results1, results2, results3))
+        self.assertEqual(len(results1), 0)
+        self.assertEqual(len(results2), self.N-1)
+        self.assertEqual(len(results3), self.N)
+
+    @classmethod
+    def _test_timeout_f(cls, barrier, results):
+        i = barrier.wait()
+        if i == cls.N//2:
+            # One thread is late!
+            time.sleep(1.0)
+        try:
+            barrier.wait(0.5)
+        except threading.BrokenBarrierError:
+            results.append(True)
+
+    def test_timeout(self):
+        """
+        Test wait(timeout)
+        """
+        results = self.DummyList()
+        self.run_threads(self._test_timeout_f, (self.barrier, results))
+        self.assertEqual(len(results), self.barrier.parties)
+
+    @classmethod
+    def _test_default_timeout_f(cls, barrier, results):
+        i = barrier.wait(cls.defaultTimeout)
+        if i == cls.N//2:
+            # One thread is later than the default timeout
+            time.sleep(1.0)
+        try:
+            barrier.wait()
+        except threading.BrokenBarrierError:
+            results.append(True)
+
+    def test_default_timeout(self):
+        """
+        Test the barrier's default timeout
+        """
+        barrier = self.Barrier(self.N, timeout=0.5)
+        results = self.DummyList()
+        self.run_threads(self._test_default_timeout_f, (barrier, results))
+        self.assertEqual(len(results), barrier.parties)
+
+    def test_single_thread(self):
+        b = self.Barrier(1)
+        b.wait()
+        b.wait()
+
+    @classmethod
+    def _test_thousand_f(cls, barrier, passes, conn, lock):
+        for i in range(passes):
+            barrier.wait()
+            with lock:
+                conn.send(i)
+
+    def test_thousand(self):
+        if self.TYPE == 'manager':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+        passes = 1000
+        lock = self.Lock()
+        conn, child_conn = self.Pipe(False)
+        for j in range(self.N):
+            p = self.Process(target=self._test_thousand_f,
+                           args=(self.barrier, passes, child_conn, lock))
+            p.start()
+            self.addCleanup(p.join)
+
+        for i in range(passes):
+            for j in range(self.N):
+                self.assertEqual(conn.recv(), i)
+
+#
+#
+#
+
+class _TestValue(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes',)
+
+    codes_values = [
+        ('i', 4343, 24234),
+        ('d', 3.625, -4.25),
+        ('h', -232, 234),
+        ('q', 2 ** 33, 2 ** 34),
+        ('c', latin('x'), latin('y'))
+        ]
+
+    def setUp(self):
+        if not HAS_SHAREDCTYPES:
+            self.skipTest("requires multiprocess.sharedctypes")
+
+    @classmethod
+    def _test(cls, values):
+        for sv, cv in zip(values, cls.codes_values):
+            sv.value = cv[2]
+
+
+    def test_value(self, raw=False):
+        if raw:
+            values = [self.RawValue(code, value)
+                      for code, value, _ in self.codes_values]
+        else:
+            values = [self.Value(code, value)
+                      for code, value, _ in self.codes_values]
+
+        for sv, cv in zip(values, self.codes_values):
+            self.assertEqual(sv.value, cv[1])
+
+        proc = self.Process(target=self._test, args=(values,))
+        proc.daemon = True
+        proc.start()
+        proc.join()
+
+        for sv, cv in zip(values, self.codes_values):
+            self.assertEqual(sv.value, cv[2])
+
+    def test_rawvalue(self):
+        self.test_value(raw=True)
+
+    def test_getobj_getlock(self):
+        val1 = self.Value('i', 5)
+        lock1 = val1.get_lock()
+        obj1 = val1.get_obj()
+
+        val2 = self.Value('i', 5, lock=None)
+        lock2 = val2.get_lock()
+        obj2 = val2.get_obj()
+
+        lock = self.Lock()
+        val3 = self.Value('i', 5, lock=lock)
+        lock3 = val3.get_lock()
+        obj3 = val3.get_obj()
+        self.assertEqual(lock, lock3)
+
+        arr4 = self.Value('i', 5, lock=False)
+        self.assertFalse(hasattr(arr4, 'get_lock'))
+        self.assertFalse(hasattr(arr4, 'get_obj'))
+
+        self.assertRaises(AttributeError, self.Value, 'i', 5, lock='navalue')
+
+        arr5 = self.RawValue('i', 5)
+        self.assertFalse(hasattr(arr5, 'get_lock'))
+        self.assertFalse(hasattr(arr5, 'get_obj'))
+
+
+class _TestArray(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes',)
+
+    @classmethod
+    def f(cls, seq):
+        for i in range(1, len(seq)):
+            seq[i] += seq[i-1]
+
+    @unittest.skipIf(c_int is None, "requires _ctypes")
+    def test_array(self, raw=False):
+        seq = [680, 626, 934, 821, 150, 233, 548, 982, 714, 831]
+        if raw:
+            arr = self.RawArray('i', seq)
+        else:
+            arr = self.Array('i', seq)
+
+        self.assertEqual(len(arr), len(seq))
+        self.assertEqual(arr[3], seq[3])
+        self.assertEqual(list(arr[2:7]), list(seq[2:7]))
+
+        arr[4:8] = seq[4:8] = array.array('i', [1, 2, 3, 4])
+
+        self.assertEqual(list(arr[:]), seq)
+
+        self.f(seq)
+
+        p = self.Process(target=self.f, args=(arr,))
+        p.daemon = True
+        p.start()
+        p.join()
+
+        self.assertEqual(list(arr[:]), seq)
+
+    @unittest.skipIf(c_int is None, "requires _ctypes")
+    def test_array_from_size(self):
+        size = 10
+        # Test for zeroing (see issue #11675).
+        # The repetition below strengthens the test by increasing the chances
+        # of previously allocated non-zero memory being used for the new array
+        # on the 2nd and 3rd loops.
+        for _ in range(3):
+            arr = self.Array('i', size)
+            self.assertEqual(len(arr), size)
+            self.assertEqual(list(arr), [0] * size)
+            arr[:] = range(10)
+            self.assertEqual(list(arr), list(range(10)))
+            del arr
+
+    @unittest.skipIf(c_int is None, "requires _ctypes")
+    def test_rawarray(self):
+        self.test_array(raw=True)
+
+    @unittest.skipIf(c_int is None, "requires _ctypes")
+    def test_getobj_getlock_obj(self):
+        arr1 = self.Array('i', list(range(10)))
+        lock1 = arr1.get_lock()
+        obj1 = arr1.get_obj()
+
+        arr2 = self.Array('i', list(range(10)), lock=None)
+        lock2 = arr2.get_lock()
+        obj2 = arr2.get_obj()
+
+        lock = self.Lock()
+        arr3 = self.Array('i', list(range(10)), lock=lock)
+        lock3 = arr3.get_lock()
+        obj3 = arr3.get_obj()
+        self.assertEqual(lock, lock3)
+
+        arr4 = self.Array('i', range(10), lock=False)
+        self.assertFalse(hasattr(arr4, 'get_lock'))
+        self.assertFalse(hasattr(arr4, 'get_obj'))
+        self.assertRaises(AttributeError,
+                          self.Array, 'i', range(10), lock='notalock')
+
+        arr5 = self.RawArray('i', range(10))
+        self.assertFalse(hasattr(arr5, 'get_lock'))
+        self.assertFalse(hasattr(arr5, 'get_obj'))
+
+#
+#
+#
+
+class _TestContainers(BaseTestCase):
+
+    ALLOWED_TYPES = ('manager',)
+
+    def test_list(self):
+        a = self.list(list(range(10)))
+        self.assertEqual(a[:], list(range(10)))
+
+        b = self.list()
+        self.assertEqual(b[:], [])
+
+        b.extend(list(range(5)))
+        self.assertEqual(b[:], list(range(5)))
+
+        self.assertEqual(b[2], 2)
+        self.assertEqual(b[2:10], [2,3,4])
+
+        b *= 2
+        self.assertEqual(b[:], [0, 1, 2, 3, 4, 0, 1, 2, 3, 4])
+
+        self.assertEqual(b + [5, 6], [0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 5, 6])
+
+        self.assertEqual(a[:], list(range(10)))
+
+        d = [a, b]
+        e = self.list(d)
+        self.assertEqual(
+            [element[:] for element in e],
+            [[0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [0, 1, 2, 3, 4, 0, 1, 2, 3, 4]]
+            )
+
+        f = self.list([a])
+        a.append('hello')
+        self.assertEqual(f[0][:], [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 'hello'])
+
+    def test_list_iter(self):
+        a = self.list(list(range(10)))
+        it = iter(a)
+        self.assertEqual(list(it), list(range(10)))
+        self.assertEqual(list(it), [])  # exhausted
+        # list modified during iteration
+        it = iter(a)
+        a[0] = 100
+        self.assertEqual(next(it), 100)
+
+    def test_list_proxy_in_list(self):
+        a = self.list([self.list(range(3)) for _i in range(3)])
+        self.assertEqual([inner[:] for inner in a], [[0, 1, 2]] * 3)
+
+        a[0][-1] = 55
+        self.assertEqual(a[0][:], [0, 1, 55])
+        for i in range(1, 3):
+            self.assertEqual(a[i][:], [0, 1, 2])
+
+        self.assertEqual(a[1].pop(), 2)
+        self.assertEqual(len(a[1]), 2)
+        for i in range(0, 3, 2):
+            self.assertEqual(len(a[i]), 3)
+
+        del a
+
+        b = self.list()
+        b.append(b)
+        del b
+
+    def test_dict(self):
+        d = self.dict()
+        indices = list(range(65, 70))
+        for i in indices:
+            d[i] = chr(i)
+        self.assertEqual(d.copy(), dict((i, chr(i)) for i in indices))
+        self.assertEqual(sorted(d.keys()), indices)
+        self.assertEqual(sorted(d.values()), [chr(i) for i in indices])
+        self.assertEqual(sorted(d.items()), [(i, chr(i)) for i in indices])
+
+    def test_dict_iter(self):
+        d = self.dict()
+        indices = list(range(65, 70))
+        for i in indices:
+            d[i] = chr(i)
+        it = iter(d)
+        self.assertEqual(list(it), indices)
+        self.assertEqual(list(it), [])  # exhausted
+        # dictionary changed size during iteration
+        it = iter(d)
+        d.clear()
+        self.assertRaises(RuntimeError, next, it)
+
+    def test_dict_proxy_nested(self):
+        pets = self.dict(ferrets=2, hamsters=4)
+        supplies = self.dict(water=10, feed=3)
+        d = self.dict(pets=pets, supplies=supplies)
+
+        self.assertEqual(supplies['water'], 10)
+        self.assertEqual(d['supplies']['water'], 10)
+
+        d['supplies']['blankets'] = 5
+        self.assertEqual(supplies['blankets'], 5)
+        self.assertEqual(d['supplies']['blankets'], 5)
+
+        d['supplies']['water'] = 7
+        self.assertEqual(supplies['water'], 7)
+        self.assertEqual(d['supplies']['water'], 7)
+
+        del pets
+        del supplies
+        self.assertEqual(d['pets']['ferrets'], 2)
+        d['supplies']['blankets'] = 11
+        self.assertEqual(d['supplies']['blankets'], 11)
+
+        pets = d['pets']
+        supplies = d['supplies']
+        supplies['water'] = 7
+        self.assertEqual(supplies['water'], 7)
+        self.assertEqual(d['supplies']['water'], 7)
+
+        d.clear()
+        self.assertEqual(len(d), 0)
+        self.assertEqual(supplies['water'], 7)
+        self.assertEqual(pets['hamsters'], 4)
+
+        l = self.list([pets, supplies])
+        l[0]['marmots'] = 1
+        self.assertEqual(pets['marmots'], 1)
+        self.assertEqual(l[0]['marmots'], 1)
+
+        del pets
+        del supplies
+        self.assertEqual(l[0]['marmots'], 1)
+
+        outer = self.list([[88, 99], l])
+        self.assertIsInstance(outer[0], list)  # Not a ListProxy
+        self.assertEqual(outer[-1][-1]['feed'], 3)
+
+    def test_nested_queue(self):
+        a = self.list() # Test queue inside list
+        a.append(self.Queue())
+        a[0].put(123)
+        self.assertEqual(a[0].get(), 123)
+        b = self.dict() # Test queue inside dict
+        b[0] = self.Queue()
+        b[0].put(456)
+        self.assertEqual(b[0].get(), 456)
+
+    def test_namespace(self):
+        n = self.Namespace()
+        n.name = 'Bob'
+        n.job = 'Builder'
+        n._hidden = 'hidden'
+        self.assertEqual((n.name, n.job), ('Bob', 'Builder'))
+        del n.job
+        self.assertEqual(str(n), "Namespace(name='Bob')")
+        self.assertTrue(hasattr(n, 'name'))
+        self.assertTrue(not hasattr(n, 'job'))
+
+#
+#
+#
+
+def sqr(x, wait=0.0):
+    time.sleep(wait)
+    return x*x
+
+def mul(x, y):
+    return x*y
+
+def raise_large_valuerror(wait):
+    time.sleep(wait)
+    raise ValueError("x" * 1024**2)
+
+def identity(x):
+    return x
+
+class CountedObject(object):
+    n_instances = 0
+
+    def __new__(cls):
+        cls.n_instances += 1
+        return object.__new__(cls)
+
+    def __del__(self):
+        type(self).n_instances -= 1
+
+class SayWhenError(ValueError): pass
+
+def exception_throwing_generator(total, when):
+    if when == -1:
+        raise SayWhenError("Somebody said when")
+    for i in range(total):
+        if i == when:
+            raise SayWhenError("Somebody said when")
+        yield i
+
+
+class _TestPool(BaseTestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.pool = cls.Pool(4)
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.pool.terminate()
+        cls.pool.join()
+        cls.pool = None
+        super().tearDownClass()
+
+    def test_apply(self):
+        papply = self.pool.apply
+        self.assertEqual(papply(sqr, (5,)), sqr(5))
+        self.assertEqual(papply(sqr, (), {'x':3}), sqr(x=3))
+
+    def test_map(self):
+        pmap = self.pool.map
+        self.assertEqual(pmap(sqr, list(range(10))), list(map(sqr, list(range(10)))))
+        self.assertEqual(pmap(sqr, list(range(100)), chunksize=20),
+                         list(map(sqr, list(range(100)))))
+
+    def test_starmap(self):
+        psmap = self.pool.starmap
+        tuples = list(zip(range(10), range(9,-1, -1)))
+        self.assertEqual(psmap(mul, tuples),
+                         list(itertools.starmap(mul, tuples)))
+        tuples = list(zip(range(100), range(99,-1, -1)))
+        self.assertEqual(psmap(mul, tuples, chunksize=20),
+                         list(itertools.starmap(mul, tuples)))
+
+    def test_starmap_async(self):
+        tuples = list(zip(range(100), range(99,-1, -1)))
+        self.assertEqual(self.pool.starmap_async(mul, tuples).get(),
+                         list(itertools.starmap(mul, tuples)))
+
+    def test_map_async(self):
+        self.assertEqual(self.pool.map_async(sqr, list(range(10))).get(),
+                         list(map(sqr, list(range(10)))))
+
+    def test_map_async_callbacks(self):
+        call_args = self.manager.list() if self.TYPE == 'manager' else []
+        self.pool.map_async(int, ['1'],
+                            callback=call_args.append,
+                            error_callback=call_args.append).wait()
+        self.assertEqual(1, len(call_args))
+        self.assertEqual([1], call_args[0])
+        self.pool.map_async(int, ['a'],
+                            callback=call_args.append,
+                            error_callback=call_args.append).wait()
+        self.assertEqual(2, len(call_args))
+        self.assertIsInstance(call_args[1], ValueError)
+
+    def test_map_unplicklable(self):
+        # Issue #19425 -- failure to pickle should not cause a hang
+        if self.TYPE == 'threads':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+        class A(object):
+            def __reduce__(self):
+                raise RuntimeError('cannot pickle')
+        with self.assertRaises(RuntimeError):
+            self.pool.map(sqr, [A()]*10)
+
+    def test_map_chunksize(self):
+        try:
+            self.pool.map_async(sqr, [], chunksize=1).get(timeout=TIMEOUT1)
+        except multiprocessing.TimeoutError:
+            self.fail("pool.map_async with chunksize stalled on null list")
+
+    def test_map_handle_iterable_exception(self):
+        if self.TYPE == 'manager':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        # SayWhenError seen at the very first of the iterable
+        with self.assertRaises(SayWhenError):
+            self.pool.map(sqr, exception_throwing_generator(1, -1), 1)
+        # again, make sure it's reentrant
+        with self.assertRaises(SayWhenError):
+            self.pool.map(sqr, exception_throwing_generator(1, -1), 1)
+
+        with self.assertRaises(SayWhenError):
+            self.pool.map(sqr, exception_throwing_generator(10, 3), 1)
+
+        class SpecialIterable:
+            def __iter__(self):
+                return self
+            def __next__(self):
+                raise SayWhenError
+            def __len__(self):
+                return 1
+        with self.assertRaises(SayWhenError):
+            self.pool.map(sqr, SpecialIterable(), 1)
+        with self.assertRaises(SayWhenError):
+            self.pool.map(sqr, SpecialIterable(), 1)
+
+    def test_async(self):
+        res = self.pool.apply_async(sqr, (7, TIMEOUT1,))
+        get = TimingWrapper(res.get)
+        self.assertEqual(get(), 49)
+        self.assertTimingAlmostEqual(get.elapsed, TIMEOUT1)
+
+    def test_async_timeout(self):
+        res = self.pool.apply_async(sqr, (6, TIMEOUT2 + 1.0))
+        get = TimingWrapper(res.get)
+        self.assertRaises(multiprocessing.TimeoutError, get, timeout=TIMEOUT2)
+        self.assertTimingAlmostEqual(get.elapsed, TIMEOUT2)
+
+    def test_imap(self):
+        it = self.pool.imap(sqr, list(range(10)))
+        self.assertEqual(list(it), list(map(sqr, list(range(10)))))
+
+        it = self.pool.imap(sqr, list(range(10)))
+        for i in range(10):
+            self.assertEqual(next(it), i*i)
+        self.assertRaises(StopIteration, it.__next__)
+
+        it = self.pool.imap(sqr, list(range(1000)), chunksize=100)
+        for i in range(1000):
+            self.assertEqual(next(it), i*i)
+        self.assertRaises(StopIteration, it.__next__)
+
+    def test_imap_handle_iterable_exception(self):
+        if self.TYPE == 'manager':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        # SayWhenError seen at the very first of the iterable
+        it = self.pool.imap(sqr, exception_throwing_generator(1, -1), 1)
+        self.assertRaises(SayWhenError, it.__next__)
+        # again, make sure it's reentrant
+        it = self.pool.imap(sqr, exception_throwing_generator(1, -1), 1)
+        self.assertRaises(SayWhenError, it.__next__)
+
+        it = self.pool.imap(sqr, exception_throwing_generator(10, 3), 1)
+        for i in range(3):
+            self.assertEqual(next(it), i*i)
+        self.assertRaises(SayWhenError, it.__next__)
+
+        # SayWhenError seen at start of problematic chunk's results
+        it = self.pool.imap(sqr, exception_throwing_generator(20, 7), 2)
+        for i in range(6):
+            self.assertEqual(next(it), i*i)
+        self.assertRaises(SayWhenError, it.__next__)
+        it = self.pool.imap(sqr, exception_throwing_generator(20, 7), 4)
+        for i in range(4):
+            self.assertEqual(next(it), i*i)
+        self.assertRaises(SayWhenError, it.__next__)
+
+    def test_imap_unordered(self):
+        it = self.pool.imap_unordered(sqr, list(range(10)))
+        self.assertEqual(sorted(it), list(map(sqr, list(range(10)))))
+
+        it = self.pool.imap_unordered(sqr, list(range(1000)), chunksize=100)
+        self.assertEqual(sorted(it), list(map(sqr, list(range(1000)))))
+
+    def test_imap_unordered_handle_iterable_exception(self):
+        if self.TYPE == 'manager':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        # SayWhenError seen at the very first of the iterable
+        it = self.pool.imap_unordered(sqr,
+                                      exception_throwing_generator(1, -1),
+                                      1)
+        self.assertRaises(SayWhenError, it.__next__)
+        # again, make sure it's reentrant
+        it = self.pool.imap_unordered(sqr,
+                                      exception_throwing_generator(1, -1),
+                                      1)
+        self.assertRaises(SayWhenError, it.__next__)
+
+        it = self.pool.imap_unordered(sqr,
+                                      exception_throwing_generator(10, 3),
+                                      1)
+        expected_values = list(map(sqr, list(range(10))))
+        with self.assertRaises(SayWhenError):
+            # imap_unordered makes it difficult to anticipate the SayWhenError
+            for i in range(10):
+                value = next(it)
+                self.assertIn(value, expected_values)
+                expected_values.remove(value)
+
+        it = self.pool.imap_unordered(sqr,
+                                      exception_throwing_generator(20, 7),
+                                      2)
+        expected_values = list(map(sqr, list(range(20))))
+        with self.assertRaises(SayWhenError):
+            for i in range(20):
+                value = next(it)
+                self.assertIn(value, expected_values)
+                expected_values.remove(value)
+
+    def test_make_pool(self):
+        expected_error = (RemoteError if self.TYPE == 'manager'
+                          else ValueError)
+
+        self.assertRaises(expected_error, self.Pool, -1)
+        self.assertRaises(expected_error, self.Pool, 0)
+
+        if self.TYPE != 'manager':
+            p = self.Pool(3)
+            try:
+                self.assertEqual(3, len(p._pool))
+            finally:
+                p.close()
+                p.join()
+
+    def test_terminate(self):
+        result = self.pool.map_async(
+            time.sleep, [0.1 for i in range(10000)], chunksize=1
+            )
+        self.pool.terminate()
+        join = TimingWrapper(self.pool.join)
+        join()
+        # Sanity check the pool didn't wait for all tasks to finish
+        self.assertLess(join.elapsed, 2.0)
+
+    def test_empty_iterable(self):
+        # See Issue 12157
+        p = self.Pool(1)
+
+        self.assertEqual(p.map(sqr, []), [])
+        self.assertEqual(list(p.imap(sqr, [])), [])
+        self.assertEqual(list(p.imap_unordered(sqr, [])), [])
+        self.assertEqual(p.map_async(sqr, []).get(), [])
+
+        p.close()
+        p.join()
+
+    def test_context(self):
+        if self.TYPE == 'processes':
+            L = list(range(10))
+            expected = [sqr(i) for i in L]
+            with self.Pool(2) as p:
+                r = p.map_async(sqr, L)
+                self.assertEqual(r.get(), expected)
+            p.join()
+            self.assertRaises(ValueError, p.map_async, sqr, L)
+
+    @classmethod
+    def _test_traceback(cls):
+        raise RuntimeError(123) # some comment
+
+    @unittest.skipIf(True, "fails with is_dill(obj, child=True)")
+    def test_traceback(self):
+        # We want ensure that the traceback from the child process is
+        # contained in the traceback raised in the main process.
+        if self.TYPE == 'processes':
+            with self.Pool(1) as p:
+                try:
+                    p.apply(self._test_traceback)
+                except Exception as e:
+                    exc = e
+                else:
+                    self.fail('expected RuntimeError')
+            p.join()
+            self.assertIs(type(exc), RuntimeError)
+            self.assertEqual(exc.args, (123,))
+            cause = exc.__cause__
+            self.assertIs(type(cause), multiprocessing.pool.RemoteTraceback)
+            self.assertIn('raise RuntimeError(123) # some comment', cause.tb)
+
+            with test.support.captured_stderr() as f1:
+                try:
+                    raise exc
+                except RuntimeError:
+                    sys.excepthook(*sys.exc_info())
+            self.assertIn('raise RuntimeError(123) # some comment',
+                          f1.getvalue())
+            # _helper_reraises_exception should not make the error
+            # a remote exception
+            with self.Pool(1) as p:
+                try:
+                    p.map(sqr, exception_throwing_generator(1, -1), 1)
+                except Exception as e:
+                    exc = e
+                else:
+                    self.fail('expected SayWhenError')
+                self.assertIs(type(exc), SayWhenError)
+                self.assertIs(exc.__cause__, None)
+            p.join()
+
+    @classmethod
+    def _test_wrapped_exception(cls):
+        raise RuntimeError('foo')
+
+    @unittest.skipIf(True, "fails with is_dill(obj, child=True)")
+    def test_wrapped_exception(self):
+        # Issue #20980: Should not wrap exception when using thread pool
+        with self.Pool(1) as p:
+            with self.assertRaises(RuntimeError):
+                p.apply(self._test_wrapped_exception)
+        p.join()
+
+    def test_map_no_failfast(self):
+        # Issue #23992: the fail-fast behaviour when an exception is raised
+        # during map() would make Pool.join() deadlock, because a worker
+        # process would fill the result queue (after the result handler thread
+        # terminated, hence not draining it anymore).
+
+        t_start = time.monotonic()
+
+        with self.assertRaises(ValueError):
+            with self.Pool(2) as p:
+                try:
+                    p.map(raise_large_valuerror, [0, 1])
+                finally:
+                    time.sleep(0.5)
+                    p.close()
+                    p.join()
+
+        # check that we indeed waited for all jobs
+        self.assertGreater(time.monotonic() - t_start, 0.9)
+
+    def test_release_task_refs(self):
+        # Issue #29861: task arguments and results should not be kept
+        # alive after we are done with them.
+        objs = [CountedObject() for i in range(10)]
+        refs = [weakref.ref(o) for o in objs]
+        self.pool.map(identity, objs)
+
+        del objs
+        gc.collect()  # For PyPy or other GCs.
+        time.sleep(DELTA)  # let threaded cleanup code run
+        self.assertEqual(set(wr() for wr in refs), {None})
+        # With a process pool, copies of the objects are returned, check
+        # they were released too.
+        self.assertEqual(CountedObject.n_instances, 0)
+
+    def test_enter(self):
+        if self.TYPE == 'manager':
+            self.skipTest("test not applicable to manager")
+
+        pool = self.Pool(1)
+        with pool:
+            pass
+            # call pool.terminate()
+        # pool is no longer running
+
+        with self.assertRaises(ValueError):
+            # bpo-35477: pool.__enter__() fails if the pool is not running
+            with pool:
+                pass
+        pool.join()
+
+    def test_resource_warning(self):
+        if self.TYPE == 'manager':
+            self.skipTest("test not applicable to manager")
+
+        pool = self.Pool(1)
+        pool.terminate()
+        pool.join()
+
+        # force state to RUN to emit ResourceWarning in __del__()
+        pool._state = multiprocessing.pool.RUN
+
+        with warnings_helper.check_warnings(
+                ('unclosed running multiprocessing pool', ResourceWarning)):
+            pool = None
+            support.gc_collect()
+
+def raising():
+    raise KeyError("key")
+
+def unpickleable_result():
+    return lambda: 42
+
+class _TestPoolWorkerErrors(BaseTestCase):
+    ALLOWED_TYPES = ('processes', )
+
+    def test_async_error_callback(self):
+        p = multiprocessing.Pool(2)
+
+        scratchpad = [None]
+        def errback(exc):
+            scratchpad[0] = exc
+
+        res = p.apply_async(raising, error_callback=errback)
+        self.assertRaises(KeyError, res.get)
+        self.assertTrue(scratchpad[0])
+        self.assertIsInstance(scratchpad[0], KeyError)
+
+        p.close()
+        p.join()
+
+    def _test_unpickleable_result(self):
+        from multiprocess.pool import MaybeEncodingError
+        p = multiprocessing.Pool(2)
+
+        # Make sure we don't lose pool processes because of encoding errors.
+        for iteration in range(20):
+
+            scratchpad = [None]
+            def errback(exc):
+                scratchpad[0] = exc
+
+            res = p.apply_async(unpickleable_result, error_callback=errback)
+            self.assertRaises(MaybeEncodingError, res.get)
+            wrapped = scratchpad[0]
+            self.assertTrue(wrapped)
+            self.assertIsInstance(scratchpad[0], MaybeEncodingError)
+            self.assertIsNotNone(wrapped.exc)
+            self.assertIsNotNone(wrapped.value)
+
+        p.close()
+        p.join()
+
+class _TestPoolWorkerLifetime(BaseTestCase):
+    ALLOWED_TYPES = ('processes', )
+
+    def test_pool_worker_lifetime(self):
+        p = multiprocessing.Pool(3, maxtasksperchild=10)
+        self.assertEqual(3, len(p._pool))
+        origworkerpids = [w.pid for w in p._pool]
+        # Run many tasks so each worker gets replaced (hopefully)
+        results = []
+        for i in range(100):
+            results.append(p.apply_async(sqr, (i, )))
+        # Fetch the results and verify we got the right answers,
+        # also ensuring all the tasks have completed.
+        for (j, res) in enumerate(results):
+            self.assertEqual(res.get(), sqr(j))
+        # Refill the pool
+        p._repopulate_pool()
+        # Wait until all workers are alive
+        # (countdown * DELTA = 5 seconds max startup process time)
+        countdown = 50
+        while countdown and not all(w.is_alive() for w in p._pool):
+            countdown -= 1
+            time.sleep(DELTA)
+        finalworkerpids = [w.pid for w in p._pool]
+        # All pids should be assigned.  See issue #7805.
+        self.assertNotIn(None, origworkerpids)
+        self.assertNotIn(None, finalworkerpids)
+        # Finally, check that the worker pids have changed
+        self.assertNotEqual(sorted(origworkerpids), sorted(finalworkerpids))
+        p.close()
+        p.join()
+
+    def test_pool_worker_lifetime_early_close(self):
+        # Issue #10332: closing a pool whose workers have limited lifetimes
+        # before all the tasks completed would make join() hang.
+        p = multiprocessing.Pool(3, maxtasksperchild=1)
+        results = []
+        for i in range(6):
+            results.append(p.apply_async(sqr, (i, 0.3)))
+        p.close()
+        p.join()
+        # check the results
+        for (j, res) in enumerate(results):
+            self.assertEqual(res.get(), sqr(j))
+
+    def test_pool_maxtasksperchild_invalid(self):
+        for value in [0, -1, 0.5, "12"]:
+            with self.assertRaises(ValueError):
+                multiprocessing.Pool(3, maxtasksperchild=value)
+
+    def test_worker_finalization_via_atexit_handler_of_multiprocessing(self):
+        # tests cases against bpo-38744 and bpo-39360
+        cmd = '''if 1:
+            from multiprocess import Pool
+            problem = None
+            class A:
+                def __init__(self):
+                    self.pool = Pool(processes=1)
+            def test():
+                global problem
+                problem = A()
+                problem.pool.map(float, tuple(range(10)))
+            if __name__ == "__main__":
+                test()
+        '''
+        rc, out, err = test.support.script_helper.assert_python_ok('-c', cmd, **ENV)
+        self.assertEqual(rc, 0)
+
+#
+# Test of creating a customized manager class
+#
+
+from multiprocess.managers import BaseManager, BaseProxy, RemoteError
+
+class FooBar(object):
+    def f(self):
+        return 'f()'
+    def g(self):
+        raise ValueError
+    def _h(self):
+        return '_h()'
+
+def baz():
+    for i in range(10):
+        yield i*i
+
+class IteratorProxy(BaseProxy):
+    _exposed_ = ('__next__',)
+    def __iter__(self):
+        return self
+    def __next__(self):
+        return self._callmethod('__next__')
+
+class MyManager(BaseManager):
+    pass
+
+MyManager.register('Foo', callable=FooBar)
+MyManager.register('Bar', callable=FooBar, exposed=('f', '_h'))
+MyManager.register('baz', callable=baz, proxytype=IteratorProxy)
+
+
+class _TestMyManager(BaseTestCase):
+
+    ALLOWED_TYPES = ('manager',)
+
+    def test_mymanager(self):
+        manager = MyManager()
+        manager.start()
+        self.common(manager)
+        manager.shutdown()
+
+        # bpo-30356: BaseManager._finalize_manager() sends SIGTERM
+        # to the manager process if it takes longer than 1 second to stop,
+        # which happens on slow buildbots.
+        self.assertIn(manager._process.exitcode, (0, -signal.SIGTERM))
+
+    def test_mymanager_context(self):
+        with MyManager() as manager:
+            self.common(manager)
+        # bpo-30356: BaseManager._finalize_manager() sends SIGTERM
+        # to the manager process if it takes longer than 1 second to stop,
+        # which happens on slow buildbots.
+        self.assertIn(manager._process.exitcode, (0, -signal.SIGTERM))
+
+    def test_mymanager_context_prestarted(self):
+        manager = MyManager()
+        manager.start()
+        with manager:
+            self.common(manager)
+        self.assertEqual(manager._process.exitcode, 0)
+
+    def common(self, manager):
+        foo = manager.Foo()
+        bar = manager.Bar()
+        baz = manager.baz()
+
+        foo_methods = [name for name in ('f', 'g', '_h') if hasattr(foo, name)]
+        bar_methods = [name for name in ('f', 'g', '_h') if hasattr(bar, name)]
+
+        self.assertEqual(foo_methods, ['f', 'g'])
+        self.assertEqual(bar_methods, ['f', '_h'])
+
+        self.assertEqual(foo.f(), 'f()')
+        self.assertRaises(ValueError, foo.g)
+        self.assertEqual(foo._callmethod('f'), 'f()')
+        self.assertRaises(RemoteError, foo._callmethod, '_h')
+
+        self.assertEqual(bar.f(), 'f()')
+        self.assertEqual(bar._h(), '_h()')
+        self.assertEqual(bar._callmethod('f'), 'f()')
+        self.assertEqual(bar._callmethod('_h'), '_h()')
+
+        self.assertEqual(list(baz), [i*i for i in range(10)])
+
+
+#
+# Test of connecting to a remote server and using xmlrpclib for serialization
+#
+
+_queue = pyqueue.Queue()
+def get_queue():
+    return _queue
+
+class QueueManager(BaseManager):
+    '''manager class used by server process'''
+QueueManager.register('get_queue', callable=get_queue)
+
+class QueueManager2(BaseManager):
+    '''manager class which specifies the same interface as QueueManager'''
+QueueManager2.register('get_queue')
+
+
+SERIALIZER = 'xmlrpclib'
+
+class _TestRemoteManager(BaseTestCase):
+
+    ALLOWED_TYPES = ('manager',)
+    values = ['hello world', None, True, 2.25,
+              'hall\xe5 v\xe4rlden',
+              '\u043f\u0440\u0438\u0432\u0456\u0442 \u0441\u0432\u0456\u0442',
+              b'hall\xe5 v\xe4rlden',
+             ]
+    result = values[:]
+
+    @classmethod
+    def _putter(cls, address, authkey):
+        manager = QueueManager2(
+            address=address, authkey=authkey, serializer=SERIALIZER
+            )
+        manager.connect()
+        queue = manager.get_queue()
+        # Note that xmlrpclib will deserialize object as a list not a tuple
+        queue.put(tuple(cls.values))
+
+    def test_remote(self):
+        authkey = os.urandom(32)
+
+        manager = QueueManager(
+            address=(socket_helper.HOST, 0), authkey=authkey, serializer=SERIALIZER
+            )
+        manager.start()
+        self.addCleanup(manager.shutdown)
+
+        p = self.Process(target=self._putter, args=(manager.address, authkey))
+        p.daemon = True
+        p.start()
+
+        manager2 = QueueManager2(
+            address=manager.address, authkey=authkey, serializer=SERIALIZER
+            )
+        manager2.connect()
+        queue = manager2.get_queue()
+
+        self.assertEqual(queue.get(), self.result)
+
+        # Because we are using xmlrpclib for serialization instead of
+        # pickle this will cause a serialization error.
+        self.assertRaises(Exception, queue.put, time.sleep)
+
+        # Make queue finalizer run before the server is stopped
+        del queue
+
+
+@hashlib_helper.requires_hashdigest('md5')
+class _TestManagerRestart(BaseTestCase):
+
+    @classmethod
+    def _putter(cls, address, authkey):
+        manager = QueueManager(
+            address=address, authkey=authkey, serializer=SERIALIZER)
+        manager.connect()
+        queue = manager.get_queue()
+        queue.put('hello world')
+
+    def test_rapid_restart(self):
+        authkey = os.urandom(32)
+        manager = QueueManager(
+            address=(socket_helper.HOST, 0), authkey=authkey, serializer=SERIALIZER)
+        try:
+            srvr = manager.get_server()
+            addr = srvr.address
+            # Close the connection.Listener socket which gets opened as a part
+            # of manager.get_server(). It's not needed for the test.
+            srvr.listener.close()
+            manager.start()
+
+            p = self.Process(target=self._putter, args=(manager.address, authkey))
+            p.start()
+            p.join()
+            queue = manager.get_queue()
+            self.assertEqual(queue.get(), 'hello world')
+            del queue
+        finally:
+            if hasattr(manager, "shutdown"):
+                manager.shutdown()
+
+        manager = QueueManager(
+            address=addr, authkey=authkey, serializer=SERIALIZER)
+        try:
+            manager.start()
+            self.addCleanup(manager.shutdown)
+        except OSError as e:
+            if e.errno != errno.EADDRINUSE:
+                raise
+            # Retry after some time, in case the old socket was lingering
+            # (sporadic failure on buildbots)
+            time.sleep(1.0)
+            manager = QueueManager(
+                address=addr, authkey=authkey, serializer=SERIALIZER)
+            if hasattr(manager, "shutdown"):
+                self.addCleanup(manager.shutdown)
+
+#
+#
+#
+
+SENTINEL = latin('')
+
+class _TestConnection(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes', 'threads')
+
+    @classmethod
+    def _echo(cls, conn):
+        for msg in iter(conn.recv_bytes, SENTINEL):
+            conn.send_bytes(msg)
+        conn.close()
+
+    def test_connection(self):
+        conn, child_conn = self.Pipe()
+
+        p = self.Process(target=self._echo, args=(child_conn,))
+        p.daemon = True
+        p.start()
+
+        seq = [1, 2.25, None]
+        msg = latin('hello world')
+        longmsg = msg * 10
+        arr = array.array('i', list(range(4)))
+
+        if self.TYPE == 'processes':
+            self.assertEqual(type(conn.fileno()), int)
+
+        self.assertEqual(conn.send(seq), None)
+        self.assertEqual(conn.recv(), seq)
+
+        self.assertEqual(conn.send_bytes(msg), None)
+        self.assertEqual(conn.recv_bytes(), msg)
+
+        if self.TYPE == 'processes':
+            buffer = array.array('i', [0]*10)
+            expected = list(arr) + [0] * (10 - len(arr))
+            self.assertEqual(conn.send_bytes(arr), None)
+            self.assertEqual(conn.recv_bytes_into(buffer),
+                             len(arr) * buffer.itemsize)
+            self.assertEqual(list(buffer), expected)
+
+            buffer = array.array('i', [0]*10)
+            expected = [0] * 3 + list(arr) + [0] * (10 - 3 - len(arr))
+            self.assertEqual(conn.send_bytes(arr), None)
+            self.assertEqual(conn.recv_bytes_into(buffer, 3 * buffer.itemsize),
+                             len(arr) * buffer.itemsize)
+            self.assertEqual(list(buffer), expected)
+
+            buffer = bytearray(latin(' ' * 40))
+            self.assertEqual(conn.send_bytes(longmsg), None)
+            try:
+                res = conn.recv_bytes_into(buffer)
+            except multiprocessing.BufferTooShort as e:
+                self.assertEqual(e.args, (longmsg,))
+            else:
+                self.fail('expected BufferTooShort, got %s' % res)
+
+        poll = TimingWrapper(conn.poll)
+
+        self.assertEqual(poll(), False)
+        self.assertTimingAlmostEqual(poll.elapsed, 0)
+
+        self.assertEqual(poll(-1), False)
+        self.assertTimingAlmostEqual(poll.elapsed, 0)
+
+        self.assertEqual(poll(TIMEOUT1), False)
+        self.assertTimingAlmostEqual(poll.elapsed, TIMEOUT1)
+
+        conn.send(None)
+        time.sleep(.1)
+
+        self.assertEqual(poll(TIMEOUT1), True)
+        self.assertTimingAlmostEqual(poll.elapsed, 0)
+
+        self.assertEqual(conn.recv(), None)
+
+        really_big_msg = latin('X') * (1024 * 1024 * 16)   # 16Mb
+        conn.send_bytes(really_big_msg)
+        self.assertEqual(conn.recv_bytes(), really_big_msg)
+
+        conn.send_bytes(SENTINEL)                          # tell child to quit
+        child_conn.close()
+
+        if self.TYPE == 'processes':
+            self.assertEqual(conn.readable, True)
+            self.assertEqual(conn.writable, True)
+            self.assertRaises(EOFError, conn.recv)
+            self.assertRaises(EOFError, conn.recv_bytes)
+
+        p.join()
+
+    def test_duplex_false(self):
+        reader, writer = self.Pipe(duplex=False)
+        self.assertEqual(writer.send(1), None)
+        self.assertEqual(reader.recv(), 1)
+        if self.TYPE == 'processes':
+            self.assertEqual(reader.readable, True)
+            self.assertEqual(reader.writable, False)
+            self.assertEqual(writer.readable, False)
+            self.assertEqual(writer.writable, True)
+            self.assertRaises(OSError, reader.send, 2)
+            self.assertRaises(OSError, writer.recv)
+            self.assertRaises(OSError, writer.poll)
+
+    def test_spawn_close(self):
+        # We test that a pipe connection can be closed by parent
+        # process immediately after child is spawned.  On Windows this
+        # would have sometimes failed on old versions because
+        # child_conn would be closed before the child got a chance to
+        # duplicate it.
+        conn, child_conn = self.Pipe()
+
+        p = self.Process(target=self._echo, args=(child_conn,))
+        p.daemon = True
+        p.start()
+        child_conn.close()    # this might complete before child initializes
+
+        msg = latin('hello')
+        conn.send_bytes(msg)
+        self.assertEqual(conn.recv_bytes(), msg)
+
+        conn.send_bytes(SENTINEL)
+        conn.close()
+        p.join()
+
+    def test_sendbytes(self):
+        if self.TYPE != 'processes':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        msg = latin('abcdefghijklmnopqrstuvwxyz')
+        a, b = self.Pipe()
+
+        a.send_bytes(msg)
+        self.assertEqual(b.recv_bytes(), msg)
+
+        a.send_bytes(msg, 5)
+        self.assertEqual(b.recv_bytes(), msg[5:])
+
+        a.send_bytes(msg, 7, 8)
+        self.assertEqual(b.recv_bytes(), msg[7:7+8])
+
+        a.send_bytes(msg, 26)
+        self.assertEqual(b.recv_bytes(), latin(''))
+
+        a.send_bytes(msg, 26, 0)
+        self.assertEqual(b.recv_bytes(), latin(''))
+
+        self.assertRaises(ValueError, a.send_bytes, msg, 27)
+
+        self.assertRaises(ValueError, a.send_bytes, msg, 22, 5)
+
+        self.assertRaises(ValueError, a.send_bytes, msg, 26, 1)
+
+        self.assertRaises(ValueError, a.send_bytes, msg, -1)
+
+        self.assertRaises(ValueError, a.send_bytes, msg, 4, -1)
+
+    @classmethod
+    def _is_fd_assigned(cls, fd):
+        try:
+            os.fstat(fd)
+        except OSError as e:
+            if e.errno == errno.EBADF:
+                return False
+            raise
+        else:
+            return True
+
+    @classmethod
+    def _writefd(cls, conn, data, create_dummy_fds=False):
+        if create_dummy_fds:
+            for i in range(0, 256):
+                if not cls._is_fd_assigned(i):
+                    os.dup2(conn.fileno(), i)
+        fd = reduction.recv_handle(conn)
+        if msvcrt:
+            fd = msvcrt.open_osfhandle(fd, os.O_WRONLY)
+        os.write(fd, data)
+        os.close(fd)
+
+    @unittest.skipUnless(HAS_REDUCTION, "test needs multiprocessing.reduction")
+    def test_fd_transfer(self):
+        if self.TYPE != 'processes':
+            self.skipTest("only makes sense with processes")
+        conn, child_conn = self.Pipe(duplex=True)
+
+        p = self.Process(target=self._writefd, args=(child_conn, b"foo"))
+        p.daemon = True
+        p.start()
+        self.addCleanup(os_helper.unlink, os_helper.TESTFN)
+        with open(os_helper.TESTFN, "wb") as f:
+            fd = f.fileno()
+            if msvcrt:
+                fd = msvcrt.get_osfhandle(fd)
+            reduction.send_handle(conn, fd, p.pid)
+        p.join()
+        with open(os_helper.TESTFN, "rb") as f:
+            self.assertEqual(f.read(), b"foo")
+
+    @unittest.skipUnless(HAS_REDUCTION, "test needs multiprocessing.reduction")
+    @unittest.skipIf(sys.platform == "win32",
+                     "test semantics don't make sense on Windows")
+    @unittest.skipIf(MAXFD <= 256,
+                     "largest assignable fd number is too small")
+    @unittest.skipUnless(hasattr(os, "dup2"),
+                         "test needs os.dup2()")
+    def test_large_fd_transfer(self):
+        # With fd > 256 (issue #11657)
+        if self.TYPE != 'processes':
+            self.skipTest("only makes sense with processes")
+        conn, child_conn = self.Pipe(duplex=True)
+
+        p = self.Process(target=self._writefd, args=(child_conn, b"bar", True))
+        p.daemon = True
+        p.start()
+        self.addCleanup(os_helper.unlink, os_helper.TESTFN)
+        with open(os_helper.TESTFN, "wb") as f:
+            fd = f.fileno()
+            for newfd in range(256, MAXFD):
+                if not self._is_fd_assigned(newfd):
+                    break
+            else:
+                self.fail("could not find an unassigned large file descriptor")
+            os.dup2(fd, newfd)
+            try:
+                reduction.send_handle(conn, newfd, p.pid)
+            finally:
+                os.close(newfd)
+        p.join()
+        with open(os_helper.TESTFN, "rb") as f:
+            self.assertEqual(f.read(), b"bar")
+
+    @classmethod
+    def _send_data_without_fd(self, conn):
+        os.write(conn.fileno(), b"\0")
+
+    @unittest.skipUnless(HAS_REDUCTION, "test needs multiprocessing.reduction")
+    @unittest.skipIf(sys.platform == "win32", "doesn't make sense on Windows")
+    def test_missing_fd_transfer(self):
+        # Check that exception is raised when received data is not
+        # accompanied by a file descriptor in ancillary data.
+        if self.TYPE != 'processes':
+            self.skipTest("only makes sense with processes")
+        conn, child_conn = self.Pipe(duplex=True)
+
+        p = self.Process(target=self._send_data_without_fd, args=(child_conn,))
+        p.daemon = True
+        p.start()
+        self.assertRaises(RuntimeError, reduction.recv_handle, conn)
+        p.join()
+
+    def test_context(self):
+        a, b = self.Pipe()
+
+        with a, b:
+            a.send(1729)
+            self.assertEqual(b.recv(), 1729)
+            if self.TYPE == 'processes':
+                self.assertFalse(a.closed)
+                self.assertFalse(b.closed)
+
+        if self.TYPE == 'processes':
+            self.assertTrue(a.closed)
+            self.assertTrue(b.closed)
+            self.assertRaises(OSError, a.recv)
+            self.assertRaises(OSError, b.recv)
+
+class _TestListener(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes',)
+
+    def test_multiple_bind(self):
+        for family in self.connection.families:
+            l = self.connection.Listener(family=family)
+            self.addCleanup(l.close)
+            self.assertRaises(OSError, self.connection.Listener,
+                              l.address, family)
+
+    def test_context(self):
+        with self.connection.Listener() as l:
+            with self.connection.Client(l.address) as c:
+                with l.accept() as d:
+                    c.send(1729)
+                    self.assertEqual(d.recv(), 1729)
+
+        if self.TYPE == 'processes':
+            self.assertRaises(OSError, l.accept)
+
+    @unittest.skipUnless(util.abstract_sockets_supported,
+                         "test needs abstract socket support")
+    def test_abstract_socket(self):
+        with self.connection.Listener("\0something") as listener:
+            with self.connection.Client(listener.address) as client:
+                with listener.accept() as d:
+                    client.send(1729)
+                    self.assertEqual(d.recv(), 1729)
+
+        if self.TYPE == 'processes':
+            self.assertRaises(OSError, listener.accept)
+
+
+class _TestListenerClient(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes', 'threads')
+
+    @classmethod
+    def _test(cls, address):
+        conn = cls.connection.Client(address)
+        conn.send('hello')
+        conn.close()
+
+    def test_listener_client(self):
+        for family in self.connection.families:
+            l = self.connection.Listener(family=family)
+            p = self.Process(target=self._test, args=(l.address,))
+            p.daemon = True
+            p.start()
+            conn = l.accept()
+            self.assertEqual(conn.recv(), 'hello')
+            p.join()
+            l.close()
+
+    def test_issue14725(self):
+        l = self.connection.Listener()
+        p = self.Process(target=self._test, args=(l.address,))
+        p.daemon = True
+        p.start()
+        time.sleep(1)
+        # On Windows the client process should by now have connected,
+        # written data and closed the pipe handle by now.  This causes
+        # ConnectNamdedPipe() to fail with ERROR_NO_DATA.  See Issue
+        # 14725.
+        conn = l.accept()
+        self.assertEqual(conn.recv(), 'hello')
+        conn.close()
+        p.join()
+        l.close()
+
+    def test_issue16955(self):
+        for fam in self.connection.families:
+            l = self.connection.Listener(family=fam)
+            c = self.connection.Client(l.address)
+            a = l.accept()
+            a.send_bytes(b"hello")
+            self.assertTrue(c.poll(1))
+            a.close()
+            c.close()
+            l.close()
+
+class _TestPoll(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes', 'threads')
+
+    def test_empty_string(self):
+        a, b = self.Pipe()
+        self.assertEqual(a.poll(), False)
+        b.send_bytes(b'')
+        self.assertEqual(a.poll(), True)
+        self.assertEqual(a.poll(), True)
+
+    @classmethod
+    def _child_strings(cls, conn, strings):
+        for s in strings:
+            time.sleep(0.1)
+            conn.send_bytes(s)
+        conn.close()
+
+    def test_strings(self):
+        strings = (b'hello', b'', b'a', b'b', b'', b'bye', b'', b'lop')
+        a, b = self.Pipe()
+        p = self.Process(target=self._child_strings, args=(b, strings))
+        p.start()
+
+        for s in strings:
+            for i in range(200):
+                if a.poll(0.01):
+                    break
+            x = a.recv_bytes()
+            self.assertEqual(s, x)
+
+        p.join()
+
+    @classmethod
+    def _child_boundaries(cls, r):
+        # Polling may "pull" a message in to the child process, but we
+        # don't want it to pull only part of a message, as that would
+        # corrupt the pipe for any other processes which might later
+        # read from it.
+        r.poll(5)
+
+    def test_boundaries(self):
+        r, w = self.Pipe(False)
+        p = self.Process(target=self._child_boundaries, args=(r,))
+        p.start()
+        time.sleep(2)
+        L = [b"first", b"second"]
+        for obj in L:
+            w.send_bytes(obj)
+        w.close()
+        p.join()
+        self.assertIn(r.recv_bytes(), L)
+
+    @classmethod
+    def _child_dont_merge(cls, b):
+        b.send_bytes(b'a')
+        b.send_bytes(b'b')
+        b.send_bytes(b'cd')
+
+    def test_dont_merge(self):
+        a, b = self.Pipe()
+        self.assertEqual(a.poll(0.0), False)
+        self.assertEqual(a.poll(0.1), False)
+
+        p = self.Process(target=self._child_dont_merge, args=(b,))
+        p.start()
+
+        self.assertEqual(a.recv_bytes(), b'a')
+        self.assertEqual(a.poll(1.0), True)
+        self.assertEqual(a.poll(1.0), True)
+        self.assertEqual(a.recv_bytes(), b'b')
+        self.assertEqual(a.poll(1.0), True)
+        self.assertEqual(a.poll(1.0), True)
+        self.assertEqual(a.poll(0.0), True)
+        self.assertEqual(a.recv_bytes(), b'cd')
+
+        p.join()
+
+#
+# Test of sending connection and socket objects between processes
+#
+
+@unittest.skipUnless(HAS_REDUCTION, "test needs multiprocessing.reduction")
+@hashlib_helper.requires_hashdigest('md5')
+class _TestPicklingConnections(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes',)
+
+    @classmethod
+    def tearDownClass(cls):
+        from multiprocess import resource_sharer
+        resource_sharer.stop(timeout=support.LONG_TIMEOUT)
+
+    @classmethod
+    def _listener(cls, conn, families):
+        for fam in families:
+            l = cls.connection.Listener(family=fam)
+            conn.send(l.address)
+            new_conn = l.accept()
+            conn.send(new_conn)
+            new_conn.close()
+            l.close()
+
+        l = socket.create_server((socket_helper.HOST, 0))
+        conn.send(l.getsockname())
+        new_conn, addr = l.accept()
+        conn.send(new_conn)
+        new_conn.close()
+        l.close()
+
+        conn.recv()
+
+    @classmethod
+    def _remote(cls, conn):
+        for (address, msg) in iter(conn.recv, None):
+            client = cls.connection.Client(address)
+            client.send(msg.upper())
+            client.close()
+
+        address, msg = conn.recv()
+        client = socket.socket()
+        client.connect(address)
+        client.sendall(msg.upper())
+        client.close()
+
+        conn.close()
+
+    def test_pickling(self):
+        families = self.connection.families
+
+        lconn, lconn0 = self.Pipe()
+        lp = self.Process(target=self._listener, args=(lconn0, families))
+        lp.daemon = True
+        lp.start()
+        lconn0.close()
+
+        rconn, rconn0 = self.Pipe()
+        rp = self.Process(target=self._remote, args=(rconn0,))
+        rp.daemon = True
+        rp.start()
+        rconn0.close()
+
+        for fam in families:
+            msg = ('This connection uses family %s' % fam).encode('ascii')
+            address = lconn.recv()
+            rconn.send((address, msg))
+            new_conn = lconn.recv()
+            self.assertEqual(new_conn.recv(), msg.upper())
+
+        rconn.send(None)
+
+        msg = latin('This connection uses a normal socket')
+        address = lconn.recv()
+        rconn.send((address, msg))
+        new_conn = lconn.recv()
+        buf = []
+        while True:
+            s = new_conn.recv(100)
+            if not s:
+                break
+            buf.append(s)
+        buf = b''.join(buf)
+        self.assertEqual(buf, msg.upper())
+        new_conn.close()
+
+        lconn.send(None)
+
+        rconn.close()
+        lconn.close()
+
+        lp.join()
+        rp.join()
+
+    @classmethod
+    def child_access(cls, conn):
+        w = conn.recv()
+        w.send('all is well')
+        w.close()
+
+        r = conn.recv()
+        msg = r.recv()
+        conn.send(msg*2)
+
+        conn.close()
+
+    def test_access(self):
+        # On Windows, if we do not specify a destination pid when
+        # using DupHandle then we need to be careful to use the
+        # correct access flags for DuplicateHandle(), or else
+        # DupHandle.detach() will raise PermissionError.  For example,
+        # for a read only pipe handle we should use
+        # access=FILE_GENERIC_READ.  (Unfortunately
+        # DUPLICATE_SAME_ACCESS does not work.)
+        conn, child_conn = self.Pipe()
+        p = self.Process(target=self.child_access, args=(child_conn,))
+        p.daemon = True
+        p.start()
+        child_conn.close()
+
+        r, w = self.Pipe(duplex=False)
+        conn.send(w)
+        w.close()
+        self.assertEqual(r.recv(), 'all is well')
+        r.close()
+
+        r, w = self.Pipe(duplex=False)
+        conn.send(r)
+        r.close()
+        w.send('foobar')
+        w.close()
+        self.assertEqual(conn.recv(), 'foobar'*2)
+
+        p.join()
+
+#
+#
+#
+
+class _TestHeap(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes',)
+
+    def setUp(self):
+        super().setUp()
+        # Make pristine heap for these tests
+        self.old_heap = multiprocessing.heap.BufferWrapper._heap
+        multiprocessing.heap.BufferWrapper._heap = multiprocessing.heap.Heap()
+
+    def tearDown(self):
+        multiprocessing.heap.BufferWrapper._heap = self.old_heap
+        super().tearDown()
+
+    def test_heap(self):
+        iterations = 5000
+        maxblocks = 50
+        blocks = []
+
+        # get the heap object
+        heap = multiprocessing.heap.BufferWrapper._heap
+        heap._DISCARD_FREE_SPACE_LARGER_THAN = 0
+
+        # create and destroy lots of blocks of different sizes
+        for i in range(iterations):
+            size = int(random.lognormvariate(0, 1) * 1000)
+            b = multiprocessing.heap.BufferWrapper(size)
+            blocks.append(b)
+            if len(blocks) > maxblocks:
+                i = random.randrange(maxblocks)
+                del blocks[i]
+            del b
+
+        # verify the state of the heap
+        with heap._lock:
+            all = []
+            free = 0
+            occupied = 0
+            for L in list(heap._len_to_seq.values()):
+                # count all free blocks in arenas
+                for arena, start, stop in L:
+                    all.append((heap._arenas.index(arena), start, stop,
+                                stop-start, 'free'))
+                    free += (stop-start)
+            for arena, arena_blocks in heap._allocated_blocks.items():
+                # count all allocated blocks in arenas
+                for start, stop in arena_blocks:
+                    all.append((heap._arenas.index(arena), start, stop,
+                                stop-start, 'occupied'))
+                    occupied += (stop-start)
+
+            self.assertEqual(free + occupied,
+                             sum(arena.size for arena in heap._arenas))
+
+            all.sort()
+
+            for i in range(len(all)-1):
+                (arena, start, stop) = all[i][:3]
+                (narena, nstart, nstop) = all[i+1][:3]
+                if arena != narena:
+                    # Two different arenas
+                    self.assertEqual(stop, heap._arenas[arena].size)  # last block
+                    self.assertEqual(nstart, 0)         # first block
+                else:
+                    # Same arena: two adjacent blocks
+                    self.assertEqual(stop, nstart)
+
+        # test free'ing all blocks
+        random.shuffle(blocks)
+        while blocks:
+            blocks.pop()
+
+        self.assertEqual(heap._n_frees, heap._n_mallocs)
+        self.assertEqual(len(heap._pending_free_blocks), 0)
+        self.assertEqual(len(heap._arenas), 0)
+        self.assertEqual(len(heap._allocated_blocks), 0, heap._allocated_blocks)
+        self.assertEqual(len(heap._len_to_seq), 0)
+
+    def test_free_from_gc(self):
+        # Check that freeing of blocks by the garbage collector doesn't deadlock
+        # (issue #12352).
+        # Make sure the GC is enabled, and set lower collection thresholds to
+        # make collections more frequent (and increase the probability of
+        # deadlock).
+        if not gc.isenabled():
+            gc.enable()
+            self.addCleanup(gc.disable)
+        thresholds = gc.get_threshold()
+        self.addCleanup(gc.set_threshold, *thresholds)
+        gc.set_threshold(10)
+
+        # perform numerous block allocations, with cyclic references to make
+        # sure objects are collected asynchronously by the gc
+        for i in range(5000):
+            a = multiprocessing.heap.BufferWrapper(1)
+            b = multiprocessing.heap.BufferWrapper(1)
+            # circular references
+            a.buddy = b
+            b.buddy = a
+
+#
+#
+#
+
+class _Foo(Structure):
+    _fields_ = [
+        ('x', c_int),
+        ('y', c_double),
+        ('z', c_longlong,)
+        ]
+
+class _TestSharedCTypes(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes',)
+
+    def setUp(self):
+        if not HAS_SHAREDCTYPES:
+            self.skipTest("requires multiprocess.sharedctypes")
+
+    @classmethod
+    def _double(cls, x, y, z, foo, arr, string):
+        x.value *= 2
+        y.value *= 2
+        z.value *= 2
+        foo.x *= 2
+        foo.y *= 2
+        string.value *= 2
+        for i in range(len(arr)):
+            arr[i] *= 2
+
+    def test_sharedctypes(self, lock=False):
+        x = Value('i', 7, lock=lock)
+        y = Value(c_double, 1.0/3.0, lock=lock)
+        z = Value(c_longlong, 2 ** 33, lock=lock)
+        foo = Value(_Foo, 3, 2, lock=lock)
+        arr = self.Array('d', list(range(10)), lock=lock)
+        string = self.Array('c', 20, lock=lock)
+        string.value = latin('hello')
+
+        p = self.Process(target=self._double, args=(x, y, z, foo, arr, string))
+        p.daemon = True
+        p.start()
+        p.join()
+
+        self.assertEqual(x.value, 14)
+        self.assertAlmostEqual(y.value, 2.0/3.0)
+        self.assertEqual(z.value, 2 ** 34)
+        self.assertEqual(foo.x, 6)
+        self.assertAlmostEqual(foo.y, 4.0)
+        for i in range(10):
+            self.assertAlmostEqual(arr[i], i*2)
+        self.assertEqual(string.value, latin('hellohello'))
+
+    def test_synchronize(self):
+        self.test_sharedctypes(lock=True)
+
+    def test_copy(self):
+        foo = _Foo(2, 5.0, 2 ** 33)
+        bar = copy(foo)
+        foo.x = 0
+        foo.y = 0
+        foo.z = 0
+        self.assertEqual(bar.x, 2)
+        self.assertAlmostEqual(bar.y, 5.0)
+        self.assertEqual(bar.z, 2 ** 33)
+
+
+@unittest.skipUnless(HAS_SHMEM, "requires multiprocess.shared_memory")
+@hashlib_helper.requires_hashdigest('md5')
+class _TestSharedMemory(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes',)
+
+    @staticmethod
+    def _attach_existing_shmem_then_write(shmem_name_or_obj, binary_data):
+        if isinstance(shmem_name_or_obj, str):
+            local_sms = shared_memory.SharedMemory(shmem_name_or_obj)
+        else:
+            local_sms = shmem_name_or_obj
+        local_sms.buf[:len(binary_data)] = binary_data
+        local_sms.close()
+
+    def _new_shm_name(self, prefix):
+        # Add a PID to the name of a POSIX shared memory object to allow
+        # running multiprocessing tests (test_multiprocessing_fork,
+        # test_multiprocessing_spawn, etc) in parallel.
+        return prefix + str(os.getpid())
+
+    def test_shared_memory_basics(self):
+        name_tsmb = self._new_shm_name('test01_tsmb')
+        sms = shared_memory.SharedMemory(name_tsmb, create=True, size=512)
+        self.addCleanup(sms.unlink)
+
+        # Verify attributes are readable.
+        self.assertEqual(sms.name, name_tsmb)
+        self.assertGreaterEqual(sms.size, 512)
+        self.assertGreaterEqual(len(sms.buf), sms.size)
+
+        # Verify __repr__
+        self.assertIn(sms.name, str(sms))
+        self.assertIn(str(sms.size), str(sms))
+
+        # Modify contents of shared memory segment through memoryview.
+        sms.buf[0] = 42
+        self.assertEqual(sms.buf[0], 42)
+
+        # Attach to existing shared memory segment.
+        also_sms = shared_memory.SharedMemory(name_tsmb)
+        self.assertEqual(also_sms.buf[0], 42)
+        also_sms.close()
+
+        # Attach to existing shared memory segment but specify a new size.
+        same_sms = shared_memory.SharedMemory(name_tsmb, size=20*sms.size)
+        self.assertLess(same_sms.size, 20*sms.size)  # Size was ignored.
+        same_sms.close()
+
+        # Creating Shared Memory Segment with -ve size
+        with self.assertRaises(ValueError):
+            shared_memory.SharedMemory(create=True, size=-2)
+
+        # Attaching Shared Memory Segment without a name
+        with self.assertRaises(ValueError):
+            shared_memory.SharedMemory(create=False)
+
+        # Test if shared memory segment is created properly,
+        # when _make_filename returns an existing shared memory segment name
+        with unittest.mock.patch(
+            'multiprocess.shared_memory._make_filename') as mock_make_filename:
+
+            NAME_PREFIX = shared_memory._SHM_NAME_PREFIX
+            names = [self._new_shm_name('test01_fn'), self._new_shm_name('test02_fn')]
+            # Prepend NAME_PREFIX which can be '/psm_' or 'wnsm_', necessary
+            # because some POSIX compliant systems require name to start with /
+            names = [NAME_PREFIX + name for name in names]
+
+            mock_make_filename.side_effect = names
+            shm1 = shared_memory.SharedMemory(create=True, size=1)
+            self.addCleanup(shm1.unlink)
+            self.assertEqual(shm1._name, names[0])
+
+            mock_make_filename.side_effect = names
+            shm2 = shared_memory.SharedMemory(create=True, size=1)
+            self.addCleanup(shm2.unlink)
+            self.assertEqual(shm2._name, names[1])
+
+        if shared_memory._USE_POSIX:
+            # Posix Shared Memory can only be unlinked once.  Here we
+            # test an implementation detail that is not observed across
+            # all supported platforms (since WindowsNamedSharedMemory
+            # manages unlinking on its own and unlink() does nothing).
+            # True release of shared memory segment does not necessarily
+            # happen until process exits, depending on the OS platform.
+            name_dblunlink = self._new_shm_name('test01_dblunlink')
+            sms_uno = shared_memory.SharedMemory(
+                name_dblunlink,
+                create=True,
+                size=5000
+            )
+            with self.assertRaises(FileNotFoundError):
+                try:
+                    self.assertGreaterEqual(sms_uno.size, 5000)
+
+                    sms_duo = shared_memory.SharedMemory(name_dblunlink)
+                    sms_duo.unlink()  # First shm_unlink() call.
+                    sms_duo.close()
+                    sms_uno.close()
+
+                finally:
+                    sms_uno.unlink()  # A second shm_unlink() call is bad.
+
+        with self.assertRaises(FileExistsError):
+            # Attempting to create a new shared memory segment with a
+            # name that is already in use triggers an exception.
+            there_can_only_be_one_sms = shared_memory.SharedMemory(
+                name_tsmb,
+                create=True,
+                size=512
+            )
+
+        if shared_memory._USE_POSIX:
+            # Requesting creation of a shared memory segment with the option
+            # to attach to an existing segment, if that name is currently in
+            # use, should not trigger an exception.
+            # Note:  Using a smaller size could possibly cause truncation of
+            # the existing segment but is OS platform dependent.  In the
+            # case of MacOS/darwin, requesting a smaller size is disallowed.
+            class OptionalAttachSharedMemory(shared_memory.SharedMemory):
+                _flags = os.O_CREAT | os.O_RDWR
+            ok_if_exists_sms = OptionalAttachSharedMemory(name_tsmb)
+            self.assertEqual(ok_if_exists_sms.size, sms.size)
+            ok_if_exists_sms.close()
+
+        # Attempting to attach to an existing shared memory segment when
+        # no segment exists with the supplied name triggers an exception.
+        with self.assertRaises(FileNotFoundError):
+            nonexisting_sms = shared_memory.SharedMemory('test01_notthere')
+            nonexisting_sms.unlink()  # Error should occur on prior line.
+
+        sms.close()
+
+    @unittest.skipIf(True, "fails with dill >= 0.3.5")
+    def test_shared_memory_recreate(self):
+        # Test if shared memory segment is created properly,
+        # when _make_filename returns an existing shared memory segment name
+        with unittest.mock.patch(
+            'multiprocess.shared_memory._make_filename') as mock_make_filename:
+
+            NAME_PREFIX = shared_memory._SHM_NAME_PREFIX
+            names = [self._new_shm_name('test03_fn'), self._new_shm_name('test04_fn')]
+            # Prepend NAME_PREFIX which can be '/psm_' or 'wnsm_', necessary
+            # because some POSIX compliant systems require name to start with /
+            names = [NAME_PREFIX + name for name in names]
+
+            mock_make_filename.side_effect = names
+            shm1 = shared_memory.SharedMemory(create=True, size=1)
+            self.addCleanup(shm1.unlink)
+            self.assertEqual(shm1._name, names[0])
+
+            mock_make_filename.side_effect = names
+            shm2 = shared_memory.SharedMemory(create=True, size=1)
+            self.addCleanup(shm2.unlink)
+            self.assertEqual(shm2._name, names[1])
+
+    def test_invalid_shared_memory_cration(self):
+        # Test creating a shared memory segment with negative size
+        with self.assertRaises(ValueError):
+            sms_invalid = shared_memory.SharedMemory(create=True, size=-1)
+
+        # Test creating a shared memory segment with size 0
+        with self.assertRaises(ValueError):
+            sms_invalid = shared_memory.SharedMemory(create=True, size=0)
+
+        # Test creating a shared memory segment without size argument
+        with self.assertRaises(ValueError):
+            sms_invalid = shared_memory.SharedMemory(create=True)
+
+    def test_shared_memory_pickle_unpickle(self):
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(proto=proto):
+                sms = shared_memory.SharedMemory(create=True, size=512)
+                self.addCleanup(sms.unlink)
+                sms.buf[0:6] = b'pickle'
+
+                # Test pickling
+                pickled_sms = pickle.dumps(sms, protocol=proto)
+
+                # Test unpickling
+                sms2 = pickle.loads(pickled_sms)
+                self.assertIsInstance(sms2, shared_memory.SharedMemory)
+                self.assertEqual(sms.name, sms2.name)
+                self.assertEqual(bytes(sms.buf[0:6]), b'pickle')
+                self.assertEqual(bytes(sms2.buf[0:6]), b'pickle')
+
+                # Test that unpickled version is still the same SharedMemory
+                sms.buf[0:6] = b'newval'
+                self.assertEqual(bytes(sms.buf[0:6]), b'newval')
+                self.assertEqual(bytes(sms2.buf[0:6]), b'newval')
+
+                sms2.buf[0:6] = b'oldval'
+                self.assertEqual(bytes(sms.buf[0:6]), b'oldval')
+                self.assertEqual(bytes(sms2.buf[0:6]), b'oldval')
+
+    def test_shared_memory_pickle_unpickle_dead_object(self):
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(proto=proto):
+                sms = shared_memory.SharedMemory(create=True, size=512)
+                sms.buf[0:6] = b'pickle'
+                pickled_sms = pickle.dumps(sms, protocol=proto)
+
+                # Now, we are going to kill the original object.
+                # So, unpickled one won't be able to attach to it.
+                sms.close()
+                sms.unlink()
+
+                with self.assertRaises(FileNotFoundError):
+                    pickle.loads(pickled_sms)
+
+    def test_shared_memory_across_processes(self):
+        # bpo-40135: don't define shared memory block's name in case of
+        # the failure when we run multiprocessing tests in parallel.
+        sms = shared_memory.SharedMemory(create=True, size=512)
+        self.addCleanup(sms.unlink)
+
+        # Verify remote attachment to existing block by name is working.
+        p = self.Process(
+            target=self._attach_existing_shmem_then_write,
+            args=(sms.name, b'howdy')
+        )
+        p.daemon = True
+        p.start()
+        p.join()
+        self.assertEqual(bytes(sms.buf[:5]), b'howdy')
+
+        # Verify pickling of SharedMemory instance also works.
+        p = self.Process(
+            target=self._attach_existing_shmem_then_write,
+            args=(sms, b'HELLO')
+        )
+        p.daemon = True
+        p.start()
+        p.join()
+        self.assertEqual(bytes(sms.buf[:5]), b'HELLO')
+
+        sms.close()
+
+    @unittest.skipIf(os.name != "posix", "not feasible in non-posix platforms")
+    def test_shared_memory_SharedMemoryServer_ignores_sigint(self):
+        # bpo-36368: protect SharedMemoryManager server process from
+        # KeyboardInterrupt signals.
+        smm = multiprocessing.managers.SharedMemoryManager()
+        smm.start()
+
+        # make sure the manager works properly at the beginning
+        sl = smm.ShareableList(range(10))
+
+        # the manager's server should ignore KeyboardInterrupt signals, and
+        # maintain its connection with the current process, and success when
+        # asked to deliver memory segments.
+        os.kill(smm._process.pid, signal.SIGINT)
+
+        sl2 = smm.ShareableList(range(10))
+
+        # test that the custom signal handler registered in the Manager does
+        # not affect signal handling in the parent process.
+        with self.assertRaises(KeyboardInterrupt):
+            os.kill(os.getpid(), signal.SIGINT)
+
+        smm.shutdown()
+
+    @unittest.skipIf(os.name != "posix", "resource_tracker is posix only")
+    def test_shared_memory_SharedMemoryManager_reuses_resource_tracker(self):
+        # bpo-36867: test that a SharedMemoryManager uses the
+        # same resource_tracker process as its parent.
+        cmd = '''if 1:
+            from multiprocessing.managers import SharedMemoryManager
+
+
+            smm = SharedMemoryManager()
+            smm.start()
+            sl = smm.ShareableList(range(10))
+            smm.shutdown()
+        ''' #XXX: ensure correct resource_tracker
+        rc, out, err = test.support.script_helper.assert_python_ok('-c', cmd, **ENV)
+
+        # Before bpo-36867 was fixed, a SharedMemoryManager not using the same
+        # resource_tracker process as its parent would make the parent's
+        # tracker complain about sl being leaked even though smm.shutdown()
+        # properly released sl.
+        self.assertFalse(err)
+
+    def test_shared_memory_SharedMemoryManager_basics(self):
+        smm1 = multiprocessing.managers.SharedMemoryManager()
+        with self.assertRaises(ValueError):
+            smm1.SharedMemory(size=9)  # Fails if SharedMemoryServer not started
+        smm1.start()
+        lol = [ smm1.ShareableList(range(i)) for i in range(5, 10) ]
+        lom = [ smm1.SharedMemory(size=j) for j in range(32, 128, 16) ]
+        doppleganger_list0 = shared_memory.ShareableList(name=lol[0].shm.name)
+        self.assertEqual(len(doppleganger_list0), 5)
+        doppleganger_shm0 = shared_memory.SharedMemory(name=lom[0].name)
+        self.assertGreaterEqual(len(doppleganger_shm0.buf), 32)
+        held_name = lom[0].name
+        smm1.shutdown()
+        if sys.platform != "win32":
+            # Calls to unlink() have no effect on Windows platform; shared
+            # memory will only be released once final process exits.
+            with self.assertRaises(FileNotFoundError):
+                # No longer there to be attached to again.
+                absent_shm = shared_memory.SharedMemory(name=held_name)
+
+        with multiprocessing.managers.SharedMemoryManager() as smm2:
+            sl = smm2.ShareableList("howdy")
+            shm = smm2.SharedMemory(size=128)
+            held_name = sl.shm.name
+        if sys.platform != "win32":
+            with self.assertRaises(FileNotFoundError):
+                # No longer there to be attached to again.
+                absent_sl = shared_memory.ShareableList(name=held_name)
+
+
+    def test_shared_memory_ShareableList_basics(self):
+        sl = shared_memory.ShareableList(
+            ['howdy', b'HoWdY', -273.154, 100, None, True, 42]
+        )
+        self.addCleanup(sl.shm.unlink)
+
+        # Verify __repr__
+        self.assertIn(sl.shm.name, str(sl))
+        self.assertIn(str(list(sl)), str(sl))
+
+        # Index Out of Range (get)
+        with self.assertRaises(IndexError):
+            sl[7]
+
+        # Index Out of Range (set)
+        with self.assertRaises(IndexError):
+            sl[7] = 2
+
+        # Assign value without format change (str -> str)
+        current_format = sl._get_packing_format(0)
+        sl[0] = 'howdy'
+        self.assertEqual(current_format, sl._get_packing_format(0))
+
+        # Verify attributes are readable.
+        self.assertEqual(sl.format, '8s8sdqxxxxxx?xxxxxxxx?q')
+
+        # Exercise len().
+        self.assertEqual(len(sl), 7)
+
+        # Exercise index().
+        with warnings.catch_warnings():
+            # Suppress BytesWarning when comparing against b'HoWdY'.
+            warnings.simplefilter('ignore')
+            with self.assertRaises(ValueError):
+                sl.index('100')
+            self.assertEqual(sl.index(100), 3)
+
+        # Exercise retrieving individual values.
+        self.assertEqual(sl[0], 'howdy')
+        self.assertEqual(sl[-2], True)
+
+        # Exercise iterability.
+        self.assertEqual(
+            tuple(sl),
+            ('howdy', b'HoWdY', -273.154, 100, None, True, 42)
+        )
+
+        # Exercise modifying individual values.
+        sl[3] = 42
+        self.assertEqual(sl[3], 42)
+        sl[4] = 'some'  # Change type at a given position.
+        self.assertEqual(sl[4], 'some')
+        self.assertEqual(sl.format, '8s8sdq8sxxxxxxx?q')
+        with self.assertRaisesRegex(ValueError,
+                                    "exceeds available storage"):
+            sl[4] = 'far too many'
+        self.assertEqual(sl[4], 'some')
+        sl[0] = 'encodés'  # Exactly 8 bytes of UTF-8 data
+        self.assertEqual(sl[0], 'encodés')
+        self.assertEqual(sl[1], b'HoWdY')  # no spillage
+        with self.assertRaisesRegex(ValueError,
+                                    "exceeds available storage"):
+            sl[0] = 'encodées'  # Exactly 9 bytes of UTF-8 data
+        self.assertEqual(sl[1], b'HoWdY')
+        with self.assertRaisesRegex(ValueError,
+                                    "exceeds available storage"):
+            sl[1] = b'123456789'
+        self.assertEqual(sl[1], b'HoWdY')
+
+        # Exercise count().
+        with warnings.catch_warnings():
+            # Suppress BytesWarning when comparing against b'HoWdY'.
+            warnings.simplefilter('ignore')
+            self.assertEqual(sl.count(42), 2)
+            self.assertEqual(sl.count(b'HoWdY'), 1)
+            self.assertEqual(sl.count(b'adios'), 0)
+
+        # Exercise creating a duplicate.
+        name_duplicate = self._new_shm_name('test03_duplicate')
+        sl_copy = shared_memory.ShareableList(sl, name=name_duplicate)
+        try:
+            self.assertNotEqual(sl.shm.name, sl_copy.shm.name)
+            self.assertEqual(name_duplicate, sl_copy.shm.name)
+            self.assertEqual(list(sl), list(sl_copy))
+            self.assertEqual(sl.format, sl_copy.format)
+            sl_copy[-1] = 77
+            self.assertEqual(sl_copy[-1], 77)
+            self.assertNotEqual(sl[-1], 77)
+            sl_copy.shm.close()
+        finally:
+            sl_copy.shm.unlink()
+
+        # Obtain a second handle on the same ShareableList.
+        sl_tethered = shared_memory.ShareableList(name=sl.shm.name)
+        self.assertEqual(sl.shm.name, sl_tethered.shm.name)
+        sl_tethered[-1] = 880
+        self.assertEqual(sl[-1], 880)
+        sl_tethered.shm.close()
+
+        sl.shm.close()
+
+        # Exercise creating an empty ShareableList.
+        empty_sl = shared_memory.ShareableList()
+        try:
+            self.assertEqual(len(empty_sl), 0)
+            self.assertEqual(empty_sl.format, '')
+            self.assertEqual(empty_sl.count('any'), 0)
+            with self.assertRaises(ValueError):
+                empty_sl.index(None)
+            empty_sl.shm.close()
+        finally:
+            empty_sl.shm.unlink()
+
+    def test_shared_memory_ShareableList_pickling(self):
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(proto=proto):
+                sl = shared_memory.ShareableList(range(10))
+                self.addCleanup(sl.shm.unlink)
+
+                serialized_sl = pickle.dumps(sl, protocol=proto)
+                deserialized_sl = pickle.loads(serialized_sl)
+                self.assertIsInstance(
+                    deserialized_sl, shared_memory.ShareableList)
+                self.assertEqual(deserialized_sl[-1], 9)
+                self.assertIsNot(sl, deserialized_sl)
+
+                deserialized_sl[4] = "changed"
+                self.assertEqual(sl[4], "changed")
+                sl[3] = "newvalue"
+                self.assertEqual(deserialized_sl[3], "newvalue")
+
+                larger_sl = shared_memory.ShareableList(range(400))
+                self.addCleanup(larger_sl.shm.unlink)
+                serialized_larger_sl = pickle.dumps(larger_sl, protocol=proto)
+                self.assertEqual(len(serialized_sl), len(serialized_larger_sl))
+                larger_sl.shm.close()
+
+                deserialized_sl.shm.close()
+                sl.shm.close()
+
+    def test_shared_memory_ShareableList_pickling_dead_object(self):
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(proto=proto):
+                sl = shared_memory.ShareableList(range(10))
+                serialized_sl = pickle.dumps(sl, protocol=proto)
+
+                # Now, we are going to kill the original object.
+                # So, unpickled one won't be able to attach to it.
+                sl.shm.close()
+                sl.shm.unlink()
+
+                with self.assertRaises(FileNotFoundError):
+                    pickle.loads(serialized_sl)
+
+    def test_shared_memory_cleaned_after_process_termination(self):
+        cmd = '''if 1:
+            import os, time, sys
+            from multiprocessing import shared_memory
+
+            # Create a shared_memory segment, and send the segment name
+            sm = shared_memory.SharedMemory(create=True, size=10)
+            sys.stdout.write(sm.name + '\\n')
+            sys.stdout.flush()
+            time.sleep(100)
+        '''
+        with subprocess.Popen([sys.executable, '-E', '-c', cmd],
+                              stdout=subprocess.PIPE,
+                              stderr=subprocess.PIPE) as p:
+            name = p.stdout.readline().strip().decode()
+
+            # killing abruptly processes holding reference to a shared memory
+            # segment should not leak the given memory segment.
+            p.terminate()
+            p.wait()
+
+            deadline = time.monotonic() + support.LONG_TIMEOUT
+            t = 0.1
+            while time.monotonic() < deadline:
+                time.sleep(t)
+                t = min(t*2, 5)
+                try:
+                    smm = shared_memory.SharedMemory(name, create=False)
+                except FileNotFoundError:
+                    break
+            else:
+                raise AssertionError("A SharedMemory segment was leaked after"
+                                     " a process was abruptly terminated.")
+
+            if os.name == 'posix':
+                # Without this line it was raising warnings like:
+                #   UserWarning: resource_tracker:
+                #   There appear to be 1 leaked shared_memory
+                #   objects to clean up at shutdown
+                # See: https://bugs.python.org/issue45209
+                resource_tracker.unregister(f"/{name}", "shared_memory")
+
+                # A warning was emitted by the subprocess' own
+                # resource_tracker (on Windows, shared memory segments
+                # are released automatically by the OS).
+                err = p.stderr.read().decode()
+                self.assertIn(
+                    "resource_tracker: There appear to be 1 leaked "
+                    "shared_memory objects to clean up at shutdown", err)
+
+#
+# Test to verify that `Finalize` works.
+#
+
+class _TestFinalize(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes',)
+
+    def setUp(self):
+        self.registry_backup = util._finalizer_registry.copy()
+        util._finalizer_registry.clear()
+
+    def tearDown(self):
+        gc.collect()  # For PyPy or other GCs.
+        self.assertFalse(util._finalizer_registry)
+        util._finalizer_registry.update(self.registry_backup)
+
+    @classmethod
+    def _test_finalize(cls, conn):
+        class Foo(object):
+            pass
+
+        a = Foo()
+        util.Finalize(a, conn.send, args=('a',))
+        del a           # triggers callback for a
+        gc.collect()  # For PyPy or other GCs.
+
+        b = Foo()
+        close_b = util.Finalize(b, conn.send, args=('b',))
+        close_b()       # triggers callback for b
+        close_b()       # does nothing because callback has already been called
+        del b           # does nothing because callback has already been called
+        gc.collect()  # For PyPy or other GCs.
+
+        c = Foo()
+        util.Finalize(c, conn.send, args=('c',))
+
+        d10 = Foo()
+        util.Finalize(d10, conn.send, args=('d10',), exitpriority=1)
+
+        d01 = Foo()
+        util.Finalize(d01, conn.send, args=('d01',), exitpriority=0)
+        d02 = Foo()
+        util.Finalize(d02, conn.send, args=('d02',), exitpriority=0)
+        d03 = Foo()
+        util.Finalize(d03, conn.send, args=('d03',), exitpriority=0)
+
+        util.Finalize(None, conn.send, args=('e',), exitpriority=-10)
+
+        util.Finalize(None, conn.send, args=('STOP',), exitpriority=-100)
+
+        # call multiprocessing's cleanup function then exit process without
+        # garbage collecting locals
+        util._exit_function()
+        conn.close()
+        os._exit(0)
+
+    def test_finalize(self):
+        conn, child_conn = self.Pipe()
+
+        p = self.Process(target=self._test_finalize, args=(child_conn,))
+        p.daemon = True
+        p.start()
+        p.join()
+
+        result = [obj for obj in iter(conn.recv, 'STOP')]
+        self.assertEqual(result, ['a', 'b', 'd10', 'd03', 'd02', 'd01', 'e'])
+
+    def test_thread_safety(self):
+        # bpo-24484: _run_finalizers() should be thread-safe
+        def cb():
+            pass
+
+        class Foo(object):
+            def __init__(self):
+                self.ref = self  # create reference cycle
+                # insert finalizer at random key
+                util.Finalize(self, cb, exitpriority=random.randint(1, 100))
+
+        finish = False
+        exc = None
+
+        def run_finalizers():
+            nonlocal exc
+            while not finish:
+                time.sleep(random.random() * 1e-1)
+                try:
+                    # A GC run will eventually happen during this,
+                    # collecting stale Foo's and mutating the registry
+                    util._run_finalizers()
+                except Exception as e:
+                    exc = e
+
+        def make_finalizers():
+            nonlocal exc
+            d = {}
+            while not finish:
+                try:
+                    # Old Foo's get gradually replaced and later
+                    # collected by the GC (because of the cyclic ref)
+                    d[random.getrandbits(5)] = {Foo() for i in range(10)}
+                except Exception as e:
+                    exc = e
+                    d.clear()
+
+        old_interval = sys.getswitchinterval()
+        old_threshold = gc.get_threshold()
+        try:
+            sys.setswitchinterval(1e-6)
+            gc.set_threshold(5, 5, 5)
+            threads = [threading.Thread(target=run_finalizers),
+                       threading.Thread(target=make_finalizers)]
+            with threading_helper.start_threads(threads):
+                time.sleep(4.0)  # Wait a bit to trigger race condition
+                finish = True
+            if exc is not None:
+                raise exc
+        finally:
+            sys.setswitchinterval(old_interval)
+            gc.set_threshold(*old_threshold)
+            gc.collect()  # Collect remaining Foo's
+
+
+#
+# Test that from ... import * works for each module
+#
+
+class _TestImportStar(unittest.TestCase):
+
+    def get_module_names(self):
+        import glob
+        folder = os.path.dirname(multiprocessing.__file__)
+        pattern = os.path.join(glob.escape(folder), '*.py')
+        files = glob.glob(pattern)
+        modules = [os.path.splitext(os.path.split(f)[1])[0] for f in files]
+        modules = ['multiprocess.' + m for m in modules]
+        modules.remove('multiprocess.__init__')
+        modules.append('multiprocess')
+        return modules
+
+    def test_import(self):
+        modules = self.get_module_names()
+        if sys.platform == 'win32':
+            modules.remove('multiprocess.popen_fork')
+            modules.remove('multiprocess.popen_forkserver')
+            modules.remove('multiprocess.popen_spawn_posix')
+        else:
+            modules.remove('multiprocess.popen_spawn_win32')
+            if not HAS_REDUCTION:
+                modules.remove('multiprocess.popen_forkserver')
+
+        if c_int is None:
+            # This module requires _ctypes
+            modules.remove('multiprocess.sharedctypes')
+
+        for name in modules:
+            __import__(name)
+            mod = sys.modules[name]
+            self.assertTrue(hasattr(mod, '__all__'), name)
+
+            for attr in mod.__all__:
+                self.assertTrue(
+                    hasattr(mod, attr),
+                    '%r does not have attribute %r' % (mod, attr)
+                    )
+
+#
+# Quick test that logging works -- does not test logging output
+#
+
+class _TestLogging(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes',)
+
+    def test_enable_logging(self):
+        logger = multiprocessing.get_logger()
+        logger.setLevel(util.SUBWARNING)
+        self.assertTrue(logger is not None)
+        logger.debug('this will not be printed')
+        logger.info('nor will this')
+        logger.setLevel(LOG_LEVEL)
+
+    @classmethod
+    def _test_level(cls, conn):
+        logger = multiprocessing.get_logger()
+        conn.send(logger.getEffectiveLevel())
+
+    def test_level(self):
+        LEVEL1 = 32
+        LEVEL2 = 37
+
+        logger = multiprocessing.get_logger()
+        root_logger = logging.getLogger()
+        root_level = root_logger.level
+
+        reader, writer = multiprocessing.Pipe(duplex=False)
+
+        logger.setLevel(LEVEL1)
+        p = self.Process(target=self._test_level, args=(writer,))
+        p.start()
+        self.assertEqual(LEVEL1, reader.recv())
+        p.join()
+        p.close()
+
+        logger.setLevel(logging.NOTSET)
+        root_logger.setLevel(LEVEL2)
+        p = self.Process(target=self._test_level, args=(writer,))
+        p.start()
+        self.assertEqual(LEVEL2, reader.recv())
+        p.join()
+        p.close()
+
+        root_logger.setLevel(root_level)
+        logger.setLevel(level=LOG_LEVEL)
+
+
+# class _TestLoggingProcessName(BaseTestCase):
+#
+#     def handle(self, record):
+#         assert record.processName == multiprocessing.current_process().name
+#         self.__handled = True
+#
+#     def test_logging(self):
+#         handler = logging.Handler()
+#         handler.handle = self.handle
+#         self.__handled = False
+#         # Bypass getLogger() and side-effects
+#         logger = logging.getLoggerClass()(
+#                 'multiprocessing.test.TestLoggingProcessName')
+#         logger.addHandler(handler)
+#         logger.propagate = False
+#
+#         logger.warn('foo')
+#         assert self.__handled
+
+#
+# Check that Process.join() retries if os.waitpid() fails with EINTR
+#
+
+class _TestPollEintr(BaseTestCase):
+
+    ALLOWED_TYPES = ('processes',)
+
+    @classmethod
+    def _killer(cls, pid):
+        time.sleep(0.1)
+        os.kill(pid, signal.SIGUSR1)
+
+    @unittest.skipUnless(hasattr(signal, 'SIGUSR1'), 'requires SIGUSR1')
+    def test_poll_eintr(self):
+        got_signal = [False]
+        def record(*args):
+            got_signal[0] = True
+        pid = os.getpid()
+        oldhandler = signal.signal(signal.SIGUSR1, record)
+        try:
+            killer = self.Process(target=self._killer, args=(pid,))
+            killer.start()
+            try:
+                p = self.Process(target=time.sleep, args=(2,))
+                p.start()
+                p.join()
+            finally:
+                killer.join()
+            self.assertTrue(got_signal[0])
+            self.assertEqual(p.exitcode, 0)
+        finally:
+            signal.signal(signal.SIGUSR1, oldhandler)
+
+#
+# Test to verify handle verification, see issue 3321
+#
+
+class TestInvalidHandle(unittest.TestCase):
+
+    @unittest.skipIf(WIN32, "skipped on Windows")
+    def test_invalid_handles(self):
+        conn = multiprocessing.connection.Connection(44977608)
+        # check that poll() doesn't crash
+        try:
+            conn.poll()
+        except (ValueError, OSError):
+            pass
+        finally:
+            # Hack private attribute _handle to avoid printing an error
+            # in conn.__del__
+            conn._handle = None
+        self.assertRaises((ValueError, OSError),
+                          multiprocessing.connection.Connection, -1)
+
+
+
+@hashlib_helper.requires_hashdigest('md5')
+class OtherTest(unittest.TestCase):
+    # TODO: add more tests for deliver/answer challenge.
+    def test_deliver_challenge_auth_failure(self):
+        class _FakeConnection(object):
+            def recv_bytes(self, size):
+                return b'something bogus'
+            def send_bytes(self, data):
+                pass
+        self.assertRaises(multiprocessing.AuthenticationError,
+                          multiprocessing.connection.deliver_challenge,
+                          _FakeConnection(), b'abc')
+
+    def test_answer_challenge_auth_failure(self):
+        class _FakeConnection(object):
+            def __init__(self):
+                self.count = 0
+            def recv_bytes(self, size):
+                self.count += 1
+                if self.count == 1:
+                    return multiprocessing.connection.CHALLENGE
+                elif self.count == 2:
+                    return b'something bogus'
+                return b''
+            def send_bytes(self, data):
+                pass
+        self.assertRaises(multiprocessing.AuthenticationError,
+                          multiprocessing.connection.answer_challenge,
+                          _FakeConnection(), b'abc')
+
+#
+# Test Manager.start()/Pool.__init__() initializer feature - see issue 5585
+#
+
+def initializer(ns):
+    ns.test += 1
+
+@hashlib_helper.requires_hashdigest('md5')
+class TestInitializers(unittest.TestCase):
+    def setUp(self):
+        self.mgr = multiprocessing.Manager()
+        self.ns = self.mgr.Namespace()
+        self.ns.test = 0
+
+    def tearDown(self):
+        self.mgr.shutdown()
+        self.mgr.join()
+
+    def test_manager_initializer(self):
+        m = multiprocessing.managers.SyncManager()
+        self.assertRaises(TypeError, m.start, 1)
+        m.start(initializer, (self.ns,))
+        self.assertEqual(self.ns.test, 1)
+        m.shutdown()
+        m.join()
+
+    def test_pool_initializer(self):
+        self.assertRaises(TypeError, multiprocessing.Pool, initializer=1)
+        p = multiprocessing.Pool(1, initializer, (self.ns,))
+        p.close()
+        p.join()
+        self.assertEqual(self.ns.test, 1)
+
+#
+# Issue 5155, 5313, 5331: Test process in processes
+# Verifies os.close(sys.stdin.fileno) vs. sys.stdin.close() behavior
+#
+
+def _this_sub_process(q):
+    try:
+        item = q.get(block=False)
+    except pyqueue.Empty:
+        pass
+
+def _test_process():
+    queue = multiprocessing.Queue()
+    subProc = multiprocessing.Process(target=_this_sub_process, args=(queue,))
+    subProc.daemon = True
+    subProc.start()
+    subProc.join()
+
+def _afunc(x):
+    return x*x
+
+def pool_in_process():
+    pool = multiprocessing.Pool(processes=4)
+    x = pool.map(_afunc, [1, 2, 3, 4, 5, 6, 7])
+    pool.close()
+    pool.join()
+
+class _file_like(object):
+    def __init__(self, delegate):
+        self._delegate = delegate
+        self._pid = None
+
+    @property
+    def cache(self):
+        pid = os.getpid()
+        # There are no race conditions since fork keeps only the running thread
+        if pid != self._pid:
+            self._pid = pid
+            self._cache = []
+        return self._cache
+
+    def write(self, data):
+        self.cache.append(data)
+
+    def flush(self):
+        self._delegate.write(''.join(self.cache))
+        self._cache = []
+
+class TestStdinBadfiledescriptor(unittest.TestCase):
+
+    def test_queue_in_process(self):
+        proc = multiprocessing.Process(target=_test_process)
+        proc.start()
+        proc.join()
+
+    def test_pool_in_process(self):
+        p = multiprocessing.Process(target=pool_in_process)
+        p.start()
+        p.join()
+
+    def test_flushing(self):
+        sio = io.StringIO()
+        flike = _file_like(sio)
+        flike.write('foo')
+        proc = multiprocessing.Process(target=lambda: flike.flush())
+        flike.flush()
+        assert sio.getvalue() == 'foo'
+
+
+class TestWait(unittest.TestCase):
+
+    @classmethod
+    def _child_test_wait(cls, w, slow):
+        for i in range(10):
+            if slow:
+                time.sleep(random.random()*0.1)
+            w.send((i, os.getpid()))
+        w.close()
+
+    def test_wait(self, slow=False):
+        from multiprocess.connection import wait
+        readers = []
+        procs = []
+        messages = []
+
+        for i in range(4):
+            r, w = multiprocessing.Pipe(duplex=False)
+            p = multiprocessing.Process(target=self._child_test_wait, args=(w, slow))
+            p.daemon = True
+            p.start()
+            w.close()
+            readers.append(r)
+            procs.append(p)
+            self.addCleanup(p.join)
+
+        while readers:
+            for r in wait(readers):
+                try:
+                    msg = r.recv()
+                except EOFError:
+                    readers.remove(r)
+                    r.close()
+                else:
+                    messages.append(msg)
+
+        messages.sort()
+        expected = sorted((i, p.pid) for i in range(10) for p in procs)
+        self.assertEqual(messages, expected)
+
+    @classmethod
+    def _child_test_wait_socket(cls, address, slow):
+        s = socket.socket()
+        s.connect(address)
+        for i in range(10):
+            if slow:
+                time.sleep(random.random()*0.1)
+            s.sendall(('%s\n' % i).encode('ascii'))
+        s.close()
+
+    def test_wait_socket(self, slow=False):
+        from multiprocess.connection import wait
+        l = socket.create_server((socket_helper.HOST, 0))
+        addr = l.getsockname()
+        readers = []
+        procs = []
+        dic = {}
+
+        for i in range(4):
+            p = multiprocessing.Process(target=self._child_test_wait_socket,
+                                        args=(addr, slow))
+            p.daemon = True
+            p.start()
+            procs.append(p)
+            self.addCleanup(p.join)
+
+        for i in range(4):
+            r, _ = l.accept()
+            readers.append(r)
+            dic[r] = []
+        l.close()
+
+        while readers:
+            for r in wait(readers):
+                msg = r.recv(32)
+                if not msg:
+                    readers.remove(r)
+                    r.close()
+                else:
+                    dic[r].append(msg)
+
+        expected = ''.join('%s\n' % i for i in range(10)).encode('ascii')
+        for v in dic.values():
+            self.assertEqual(b''.join(v), expected)
+
+    def test_wait_slow(self):
+        self.test_wait(True)
+
+    def test_wait_socket_slow(self):
+        self.test_wait_socket(True)
+
+    def test_wait_timeout(self):
+        from multiprocess.connection import wait
+
+        expected = 5
+        a, b = multiprocessing.Pipe()
+
+        start = time.monotonic()
+        res = wait([a, b], expected)
+        delta = time.monotonic() - start
+
+        self.assertEqual(res, [])
+        self.assertLess(delta, expected * 2)
+        self.assertGreater(delta, expected * 0.5)
+
+        b.send(None)
+
+        start = time.monotonic()
+        res = wait([a, b], 20)
+        delta = time.monotonic() - start
+
+        self.assertEqual(res, [a])
+        self.assertLess(delta, 0.4)
+
+    @classmethod
+    def signal_and_sleep(cls, sem, period):
+        sem.release()
+        time.sleep(period)
+
+    def test_wait_integer(self):
+        from multiprocess.connection import wait
+
+        expected = 3
+        sorted_ = lambda l: sorted(l, key=lambda x: id(x))
+        sem = multiprocessing.Semaphore(0)
+        a, b = multiprocessing.Pipe()
+        p = multiprocessing.Process(target=self.signal_and_sleep,
+                                    args=(sem, expected))
+
+        p.start()
+        self.assertIsInstance(p.sentinel, int)
+        self.assertTrue(sem.acquire(timeout=20))
+
+        start = time.monotonic()
+        res = wait([a, p.sentinel, b], expected + 20)
+        delta = time.monotonic() - start
+
+        self.assertEqual(res, [p.sentinel])
+        self.assertLess(delta, expected + 2)
+        self.assertGreater(delta, expected - 2)
+
+        a.send(None)
+
+        start = time.monotonic()
+        res = wait([a, p.sentinel, b], 20)
+        delta = time.monotonic() - start
+
+        self.assertEqual(sorted_(res), sorted_([p.sentinel, b]))
+        self.assertLess(delta, 0.4)
+
+        b.send(None)
+
+        start = time.monotonic()
+        res = wait([a, p.sentinel, b], 20)
+        delta = time.monotonic() - start
+
+        self.assertEqual(sorted_(res), sorted_([a, p.sentinel, b]))
+        self.assertLess(delta, 0.4)
+
+        p.terminate()
+        p.join()
+
+    def test_neg_timeout(self):
+        from multiprocess.connection import wait
+        a, b = multiprocessing.Pipe()
+        t = time.monotonic()
+        res = wait([a], timeout=-1)
+        t = time.monotonic() - t
+        self.assertEqual(res, [])
+        self.assertLess(t, 1)
+        a.close()
+        b.close()
+
+#
+# Issue 14151: Test invalid family on invalid environment
+#
+
+class TestInvalidFamily(unittest.TestCase):
+
+    @unittest.skipIf(WIN32, "skipped on Windows")
+    def test_invalid_family(self):
+        with self.assertRaises(ValueError):
+            multiprocessing.connection.Listener(r'\\.\test')
+
+    @unittest.skipUnless(WIN32, "skipped on non-Windows platforms")
+    def test_invalid_family_win32(self):
+        with self.assertRaises(ValueError):
+            multiprocessing.connection.Listener('/var/test.pipe')
+
+#
+# Issue 12098: check sys.flags of child matches that for parent
+#
+
+class TestFlags(unittest.TestCase):
+    @classmethod
+    def run_in_grandchild(cls, conn):
+        conn.send(tuple(sys.flags))
+
+    @classmethod
+    def run_in_child(cls):
+        import json
+        r, w = multiprocessing.Pipe(duplex=False)
+        p = multiprocessing.Process(target=cls.run_in_grandchild, args=(w,))
+        p.start()
+        grandchild_flags = r.recv()
+        p.join()
+        r.close()
+        w.close()
+        flags = (tuple(sys.flags), grandchild_flags)
+        print(json.dumps(flags))
+
+    def _test_flags(self):
+        import json
+        # start child process using unusual flags
+        prog = ('from multiprocess.tests import TestFlags; ' +
+                'TestFlags.run_in_child()')
+        data = subprocess.check_output(
+            [sys.executable, '-E', '-S', '-O', '-c', prog])
+        child_flags, grandchild_flags = json.loads(data.decode('ascii'))
+        self.assertEqual(child_flags, grandchild_flags)
+
+#
+# Test interaction with socket timeouts - see Issue #6056
+#
+
+class TestTimeouts(unittest.TestCase):
+    @classmethod
+    def _test_timeout(cls, child, address):
+        time.sleep(1)
+        child.send(123)
+        child.close()
+        conn = multiprocessing.connection.Client(address)
+        conn.send(456)
+        conn.close()
+
+    def test_timeout(self):
+        old_timeout = socket.getdefaulttimeout()
+        try:
+            socket.setdefaulttimeout(0.1)
+            parent, child = multiprocessing.Pipe(duplex=True)
+            l = multiprocessing.connection.Listener(family='AF_INET')
+            p = multiprocessing.Process(target=self._test_timeout,
+                                        args=(child, l.address))
+            p.start()
+            child.close()
+            self.assertEqual(parent.recv(), 123)
+            parent.close()
+            conn = l.accept()
+            self.assertEqual(conn.recv(), 456)
+            conn.close()
+            l.close()
+            join_process(p)
+        finally:
+            socket.setdefaulttimeout(old_timeout)
+
+#
+# Test what happens with no "if __name__ == '__main__'"
+#
+
+class TestNoForkBomb(unittest.TestCase):
+    def test_noforkbomb(self):
+        sm = multiprocessing.get_start_method()
+        name = os.path.join(os.path.dirname(__file__), 'mp_fork_bomb.py')
+        if sm != 'fork':
+            rc, out, err = test.support.script_helper.assert_python_failure(name, sm)
+            self.assertEqual(out, b'')
+            self.assertIn(b'RuntimeError', err)
+        else:
+            rc, out, err = test.support.script_helper.assert_python_ok(name, sm, **ENV)
+            self.assertEqual(out.rstrip(), b'123')
+            self.assertEqual(err, b'')
+
+#
+# Issue #17555: ForkAwareThreadLock
+#
+
+class TestForkAwareThreadLock(unittest.TestCase):
+    # We recursively start processes.  Issue #17555 meant that the
+    # after fork registry would get duplicate entries for the same
+    # lock.  The size of the registry at generation n was ~2**n.
+
+    @classmethod
+    def child(cls, n, conn):
+        if n > 1:
+            p = multiprocessing.Process(target=cls.child, args=(n-1, conn))
+            p.start()
+            conn.close()
+            join_process(p)
+        else:
+            conn.send(len(util._afterfork_registry))
+        conn.close()
+
+    def test_lock(self):
+        r, w = multiprocessing.Pipe(False)
+        l = util.ForkAwareThreadLock()
+        old_size = len(util._afterfork_registry)
+        p = multiprocessing.Process(target=self.child, args=(5, w))
+        p.start()
+        w.close()
+        new_size = r.recv()
+        join_process(p)
+        self.assertLessEqual(new_size, old_size)
+
+#
+# Check that non-forked child processes do not inherit unneeded fds/handles
+#
+
+class TestCloseFds(unittest.TestCase):
+
+    def get_high_socket_fd(self):
+        if WIN32:
+            # The child process will not have any socket handles, so
+            # calling socket.fromfd() should produce WSAENOTSOCK even
+            # if there is a handle of the same number.
+            return socket.socket().detach()
+        else:
+            # We want to produce a socket with an fd high enough that a
+            # freshly created child process will not have any fds as high.
+            fd = socket.socket().detach()
+            to_close = []
+            while fd < 50:
+                to_close.append(fd)
+                fd = os.dup(fd)
+            for x in to_close:
+                os.close(x)
+            return fd
+
+    def close(self, fd):
+        if WIN32:
+            socket.socket(socket.AF_INET, socket.SOCK_STREAM, fileno=fd).close()
+        else:
+            os.close(fd)
+
+    @classmethod
+    def _test_closefds(cls, conn, fd):
+        try:
+            s = socket.fromfd(fd, socket.AF_INET, socket.SOCK_STREAM)
+        except Exception as e:
+            conn.send(e)
+        else:
+            s.close()
+            conn.send(None)
+
+    def test_closefd(self):
+        if not HAS_REDUCTION:
+            raise unittest.SkipTest('requires fd pickling')
+
+        reader, writer = multiprocessing.Pipe()
+        fd = self.get_high_socket_fd()
+        try:
+            p = multiprocessing.Process(target=self._test_closefds,
+                                        args=(writer, fd))
+            p.start()
+            writer.close()
+            e = reader.recv()
+            join_process(p)
+        finally:
+            self.close(fd)
+            writer.close()
+            reader.close()
+
+        if multiprocessing.get_start_method() == 'fork':
+            self.assertIs(e, None)
+        else:
+            WSAENOTSOCK = 10038
+            self.assertIsInstance(e, OSError)
+            self.assertTrue(e.errno == errno.EBADF or
+                            e.winerror == WSAENOTSOCK, e)
+
+#
+# Issue #17097: EINTR should be ignored by recv(), send(), accept() etc
+#
+
+class TestIgnoreEINTR(unittest.TestCase):
+
+    # Sending CONN_MAX_SIZE bytes into a multiprocessing pipe must block
+    CONN_MAX_SIZE = max(support.PIPE_MAX_SIZE, support.SOCK_MAX_SIZE)
+
+    @classmethod
+    def _test_ignore(cls, conn):
+        def handler(signum, frame):
+            pass
+        signal.signal(signal.SIGUSR1, handler)
+        conn.send('ready')
+        x = conn.recv()
+        conn.send(x)
+        conn.send_bytes(b'x' * cls.CONN_MAX_SIZE)
+
+    @unittest.skipUnless(hasattr(signal, 'SIGUSR1'), 'requires SIGUSR1')
+    def test_ignore(self):
+        conn, child_conn = multiprocessing.Pipe()
+        try:
+            p = multiprocessing.Process(target=self._test_ignore,
+                                        args=(child_conn,))
+            p.daemon = True
+            p.start()
+            child_conn.close()
+            self.assertEqual(conn.recv(), 'ready')
+            time.sleep(0.1)
+            os.kill(p.pid, signal.SIGUSR1)
+            time.sleep(0.1)
+            conn.send(1234)
+            self.assertEqual(conn.recv(), 1234)
+            time.sleep(0.1)
+            os.kill(p.pid, signal.SIGUSR1)
+            self.assertEqual(conn.recv_bytes(), b'x' * self.CONN_MAX_SIZE)
+            time.sleep(0.1)
+            p.join()
+        finally:
+            conn.close()
+
+    @classmethod
+    def _test_ignore_listener(cls, conn):
+        def handler(signum, frame):
+            pass
+        signal.signal(signal.SIGUSR1, handler)
+        with multiprocessing.connection.Listener() as l:
+            conn.send(l.address)
+            a = l.accept()
+            a.send('welcome')
+
+    @unittest.skipUnless(hasattr(signal, 'SIGUSR1'), 'requires SIGUSR1')
+    def test_ignore_listener(self):
+        conn, child_conn = multiprocessing.Pipe()
+        try:
+            p = multiprocessing.Process(target=self._test_ignore_listener,
+                                        args=(child_conn,))
+            p.daemon = True
+            p.start()
+            child_conn.close()
+            address = conn.recv()
+            time.sleep(0.1)
+            os.kill(p.pid, signal.SIGUSR1)
+            time.sleep(0.1)
+            client = multiprocessing.connection.Client(address)
+            self.assertEqual(client.recv(), 'welcome')
+            p.join()
+        finally:
+            conn.close()
+
+class TestStartMethod(unittest.TestCase):
+    @classmethod
+    def _check_context(cls, conn):
+        conn.send(multiprocessing.get_start_method())
+
+    def check_context(self, ctx):
+        r, w = ctx.Pipe(duplex=False)
+        p = ctx.Process(target=self._check_context, args=(w,))
+        p.start()
+        w.close()
+        child_method = r.recv()
+        r.close()
+        p.join()
+        self.assertEqual(child_method, ctx.get_start_method())
+
+    def test_context(self):
+        for method in ('fork', 'spawn', 'forkserver'):
+            try:
+                ctx = multiprocessing.get_context(method)
+            except ValueError:
+                continue
+            self.assertEqual(ctx.get_start_method(), method)
+            self.assertIs(ctx.get_context(), ctx)
+            self.assertRaises(ValueError, ctx.set_start_method, 'spawn')
+            self.assertRaises(ValueError, ctx.set_start_method, None)
+            self.check_context(ctx)
+
+    def test_set_get(self):
+        multiprocessing.set_forkserver_preload(PRELOAD)
+        count = 0
+        old_method = multiprocessing.get_start_method()
+        try:
+            for method in ('fork', 'spawn', 'forkserver'):
+                try:
+                    multiprocessing.set_start_method(method, force=True)
+                except ValueError:
+                    continue
+                self.assertEqual(multiprocessing.get_start_method(), method)
+                ctx = multiprocessing.get_context()
+                self.assertEqual(ctx.get_start_method(), method)
+                self.assertTrue(type(ctx).__name__.lower().startswith(method))
+                self.assertTrue(
+                    ctx.Process.__name__.lower().startswith(method))
+                self.check_context(multiprocessing)
+                count += 1
+        finally:
+            multiprocessing.set_start_method(old_method, force=True)
+        self.assertGreaterEqual(count, 1)
+
+    def test_get_all(self):
+        methods = multiprocessing.get_all_start_methods()
+        if sys.platform == 'win32':
+            self.assertEqual(methods, ['spawn'])
+        else:
+            self.assertTrue(methods == ['fork', 'spawn'] or
+                            methods == ['spawn', 'fork'] or
+                            methods == ['fork', 'spawn', 'forkserver'] or
+                            methods == ['spawn', 'fork', 'forkserver'])
+
+    def test_preload_resources(self):
+        if multiprocessing.get_start_method() != 'forkserver':
+            self.skipTest("test only relevant for 'forkserver' method")
+        name = os.path.join(os.path.dirname(__file__), 'mp_preload.py')
+        rc, out, err = test.support.script_helper.assert_python_ok(name, **ENV)
+        out = out.decode()
+        err = err.decode()
+        if out.rstrip() != 'ok' or err != '':
+            print(out)
+            print(err)
+            self.fail("failed spawning forkserver or grandchild")
+
+
+@unittest.skipIf(sys.platform == "win32",
+                 "test semantics don't make sense on Windows")
+class TestResourceTracker(unittest.TestCase):
+
+    def _test_resource_tracker(self):
+        #
+        # Check that killing process does not leak named semaphores
+        #
+        cmd = '''if 1:
+            import time, os, tempfile
+            import multiprocess as mp
+            from multiprocess import resource_tracker
+            from multiprocess.shared_memory import SharedMemory
+
+            mp.set_start_method("spawn")
+            rand = tempfile._RandomNameSequence()
+
+
+            def create_and_register_resource(rtype):
+                if rtype == "semaphore":
+                    lock = mp.Lock()
+                    return lock, lock._semlock.name
+                elif rtype == "shared_memory":
+                    sm = SharedMemory(create=True, size=10)
+                    return sm, sm._name
+                else:
+                    raise ValueError(
+                        "Resource type {{}} not understood".format(rtype))
+
+
+            resource1, rname1 = create_and_register_resource("{rtype}")
+            resource2, rname2 = create_and_register_resource("{rtype}")
+
+            os.write({w}, rname1.encode("ascii") + b"\\n")
+            os.write({w}, rname2.encode("ascii") + b"\\n")
+
+            time.sleep(10)
+        '''
+        for rtype in resource_tracker._CLEANUP_FUNCS:
+            with self.subTest(rtype=rtype):
+                if rtype == "noop":
+                    # Artefact resource type used by the resource_tracker
+                    continue
+                r, w = os.pipe()
+                p = subprocess.Popen([sys.executable,
+                                     '-E', '-c', cmd.format(w=w, rtype=rtype)],
+                                     pass_fds=[w],
+                                     stderr=subprocess.PIPE)
+                os.close(w)
+                with open(r, 'rb', closefd=True) as f:
+                    name1 = f.readline().rstrip().decode('ascii')
+                    name2 = f.readline().rstrip().decode('ascii')
+                _resource_unlink(name1, rtype)
+                p.terminate()
+                p.wait()
+
+                deadline = time.monotonic() + support.LONG_TIMEOUT
+                while time.monotonic() < deadline:
+                    time.sleep(.5)
+                    try:
+                        _resource_unlink(name2, rtype)
+                    except OSError as e:
+                        # docs say it should be ENOENT, but OSX seems to give
+                        # EINVAL
+                        self.assertIn(e.errno, (errno.ENOENT, errno.EINVAL))
+                        break
+                else:
+                    raise AssertionError(
+                        f"A {rtype} resource was leaked after a process was "
+                        f"abruptly terminated.")
+                err = p.stderr.read().decode('utf-8')
+                p.stderr.close()
+                expected = ('resource_tracker: There appear to be 2 leaked {} '
+                            'objects'.format(
+                            rtype))
+                self.assertRegex(err, expected)
+                self.assertRegex(err, r'resource_tracker: %r: \[Errno' % name1)
+
+    def check_resource_tracker_death(self, signum, should_die):
+        # bpo-31310: if the semaphore tracker process has died, it should
+        # be restarted implicitly.
+        from multiprocess.resource_tracker import _resource_tracker
+        pid = _resource_tracker._pid
+        if pid is not None:
+            os.kill(pid, signal.SIGKILL)
+            support.wait_process(pid, exitcode=-signal.SIGKILL)
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore")
+            _resource_tracker.ensure_running()
+        pid = _resource_tracker._pid
+
+        os.kill(pid, signum)
+        time.sleep(1.0)  # give it time to die
+
+        ctx = multiprocessing.get_context("spawn")
+        with warnings.catch_warnings(record=True) as all_warn:
+            warnings.simplefilter("always")
+            sem = ctx.Semaphore()
+            sem.acquire()
+            sem.release()
+            wr = weakref.ref(sem)
+            # ensure `sem` gets collected, which triggers communication with
+            # the semaphore tracker
+            del sem
+            gc.collect()
+            self.assertIsNone(wr())
+            if should_die:
+                self.assertEqual(len(all_warn), 1)
+                the_warn = all_warn[0]
+                self.assertTrue(issubclass(the_warn.category, UserWarning))
+                self.assertTrue("resource_tracker: process died"
+                                in str(the_warn.message))
+            else:
+                self.assertEqual(len(all_warn), 0)
+
+    def test_resource_tracker_sigint(self):
+        # Catchable signal (ignored by semaphore tracker)
+        self.check_resource_tracker_death(signal.SIGINT, False)
+
+    def test_resource_tracker_sigterm(self):
+        # Catchable signal (ignored by semaphore tracker)
+        self.check_resource_tracker_death(signal.SIGTERM, False)
+
+    def test_resource_tracker_sigkill(self):
+        # Uncatchable signal.
+        self.check_resource_tracker_death(signal.SIGKILL, True)
+
+    @staticmethod
+    def _is_resource_tracker_reused(conn, pid):
+        from multiprocess.resource_tracker import _resource_tracker
+        _resource_tracker.ensure_running()
+        # The pid should be None in the child process, expect for the fork
+        # context. It should not be a new value.
+        reused = _resource_tracker._pid in (None, pid)
+        reused &= _resource_tracker._check_alive()
+        conn.send(reused)
+
+    def test_resource_tracker_reused(self):
+        from multiprocess.resource_tracker import _resource_tracker
+        _resource_tracker.ensure_running()
+        pid = _resource_tracker._pid
+
+        r, w = multiprocessing.Pipe(duplex=False)
+        p = multiprocessing.Process(target=self._is_resource_tracker_reused,
+                                    args=(w, pid))
+        p.start()
+        is_resource_tracker_reused = r.recv()
+
+        # Clean up
+        p.join()
+        w.close()
+        r.close()
+
+        self.assertTrue(is_resource_tracker_reused)
+
+    def test_too_long_name_resource(self):
+        # gh-96819: Resource names that will make the length of a write to a pipe
+        # greater than PIPE_BUF are not allowed
+        rtype = "shared_memory"
+        too_long_name_resource = "a" * (512 - len(rtype))
+        with self.assertRaises(ValueError):
+            resource_tracker.register(too_long_name_resource, rtype)
+
+
+class TestSimpleQueue(unittest.TestCase):
+
+    @classmethod
+    def _test_empty(cls, queue, child_can_start, parent_can_continue):
+        child_can_start.wait()
+        # issue 30301, could fail under spawn and forkserver
+        try:
+            queue.put(queue.empty())
+            queue.put(queue.empty())
+        finally:
+            parent_can_continue.set()
+
+    def test_empty(self):
+        queue = multiprocessing.SimpleQueue()
+        child_can_start = multiprocessing.Event()
+        parent_can_continue = multiprocessing.Event()
+
+        proc = multiprocessing.Process(
+            target=self._test_empty,
+            args=(queue, child_can_start, parent_can_continue)
+        )
+        proc.daemon = True
+        proc.start()
+
+        self.assertTrue(queue.empty())
+
+        child_can_start.set()
+        parent_can_continue.wait()
+
+        self.assertFalse(queue.empty())
+        self.assertEqual(queue.get(), True)
+        self.assertEqual(queue.get(), False)
+        self.assertTrue(queue.empty())
+
+        proc.join()
+
+    def test_close(self):
+        queue = multiprocessing.SimpleQueue()
+        queue.close()
+        # closing a queue twice should not fail
+        queue.close()
+
+    # Test specific to CPython since it tests private attributes
+    @test.support.cpython_only
+    def test_closed(self):
+        queue = multiprocessing.SimpleQueue()
+        queue.close()
+        self.assertTrue(queue._reader.closed)
+        self.assertTrue(queue._writer.closed)
+
+
+class TestPoolNotLeakOnFailure(unittest.TestCase):
+
+    def test_release_unused_processes(self):
+        # Issue #19675: During pool creation, if we can't create a process,
+        # don't leak already created ones.
+        will_fail_in = 3
+        forked_processes = []
+
+        class FailingForkProcess:
+            def __init__(self, **kwargs):
+                self.name = 'Fake Process'
+                self.exitcode = None
+                self.state = None
+                forked_processes.append(self)
+
+            def start(self):
+                nonlocal will_fail_in
+                if will_fail_in <= 0:
+                    raise OSError("Manually induced OSError")
+                will_fail_in -= 1
+                self.state = 'started'
+
+            def terminate(self):
+                self.state = 'stopping'
+
+            def join(self):
+                if self.state == 'stopping':
+                    self.state = 'stopped'
+
+            def is_alive(self):
+                return self.state == 'started' or self.state == 'stopping'
+
+        with self.assertRaisesRegex(OSError, 'Manually induced OSError'):
+            p = multiprocessing.pool.Pool(5, context=unittest.mock.MagicMock(
+                Process=FailingForkProcess))
+            p.close()
+            p.join()
+        self.assertFalse(
+            any(process.is_alive() for process in forked_processes))
+
+
+@hashlib_helper.requires_hashdigest('md5')
+class TestSyncManagerTypes(unittest.TestCase):
+    """Test all the types which can be shared between a parent and a
+    child process by using a manager which acts as an intermediary
+    between them.
+
+    In the following unit-tests the base type is created in the parent
+    process, the @classmethod represents the worker process and the
+    shared object is readable and editable between the two.
+
+    # The child.
+    @classmethod
+    def _test_list(cls, obj):
+        assert obj[0] == 5
+        assert obj.append(6)
+
+    # The parent.
+    def test_list(self):
+        o = self.manager.list()
+        o.append(5)
+        self.run_worker(self._test_list, o)
+        assert o[1] == 6
+    """
+    manager_class = multiprocessing.managers.SyncManager
+
+    def setUp(self):
+        self.manager = self.manager_class()
+        self.manager.start()
+        self.proc = None
+
+    def tearDown(self):
+        if self.proc is not None and self.proc.is_alive():
+            self.proc.terminate()
+            self.proc.join()
+        self.manager.shutdown()
+        self.manager = None
+        self.proc = None
+
+    @classmethod
+    def setUpClass(cls):
+        support.reap_children()
+
+    tearDownClass = setUpClass
+
+    def wait_proc_exit(self):
+        # Only the manager process should be returned by active_children()
+        # but this can take a bit on slow machines, so wait a few seconds
+        # if there are other children too (see #17395).
+        join_process(self.proc)
+        start_time = time.monotonic()
+        t = 0.01
+        while len(multiprocessing.active_children()) > 1:
+            time.sleep(t)
+            t *= 2
+            dt = time.monotonic() - start_time
+            if dt >= 5.0:
+                test.support.environment_altered = True
+                support.print_warning(f"multiprocess.Manager still has "
+                                      f"{multiprocessing.active_children()} "
+                                      f"active children after {dt} seconds")
+                break
+
+    def run_worker(self, worker, obj):
+        self.proc = multiprocessing.Process(target=worker, args=(obj, ))
+        self.proc.daemon = True
+        self.proc.start()
+        self.wait_proc_exit()
+        self.assertEqual(self.proc.exitcode, 0)
+
+    @classmethod
+    def _test_event(cls, obj):
+        assert obj.is_set()
+        obj.wait()
+        obj.clear()
+        obj.wait(0.001)
+
+    def test_event(self):
+        o = self.manager.Event()
+        o.set()
+        self.run_worker(self._test_event, o)
+        assert not o.is_set()
+        o.wait(0.001)
+
+    @classmethod
+    def _test_lock(cls, obj):
+        obj.acquire()
+
+    def test_lock(self, lname="Lock"):
+        o = getattr(self.manager, lname)()
+        self.run_worker(self._test_lock, o)
+        o.release()
+        self.assertRaises(RuntimeError, o.release)  # already released
+
+    @classmethod
+    def _test_rlock(cls, obj):
+        obj.acquire()
+        obj.release()
+
+    def test_rlock(self, lname="Lock"):
+        o = getattr(self.manager, lname)()
+        self.run_worker(self._test_rlock, o)
+
+    @classmethod
+    def _test_semaphore(cls, obj):
+        obj.acquire()
+
+    def test_semaphore(self, sname="Semaphore"):
+        o = getattr(self.manager, sname)()
+        self.run_worker(self._test_semaphore, o)
+        o.release()
+
+    def test_bounded_semaphore(self):
+        self.test_semaphore(sname="BoundedSemaphore")
+
+    @classmethod
+    def _test_condition(cls, obj):
+        obj.acquire()
+        obj.release()
+
+    def test_condition(self):
+        o = self.manager.Condition()
+        self.run_worker(self._test_condition, o)
+
+    @classmethod
+    def _test_barrier(cls, obj):
+        assert obj.parties == 5
+        obj.reset()
+
+    def test_barrier(self):
+        o = self.manager.Barrier(5)
+        self.run_worker(self._test_barrier, o)
+
+    @classmethod
+    def _test_pool(cls, obj):
+        # TODO: fix https://bugs.python.org/issue35919
+        with obj:
+            pass
+
+    def test_pool(self):
+        o = self.manager.Pool(processes=4)
+        self.run_worker(self._test_pool, o)
+
+    @classmethod
+    def _test_queue(cls, obj):
+        assert obj.qsize() == 2
+        assert obj.full()
+        assert not obj.empty()
+        assert obj.get() == 5
+        assert not obj.empty()
+        assert obj.get() == 6
+        assert obj.empty()
+
+    def test_queue(self, qname="Queue"):
+        o = getattr(self.manager, qname)(2)
+        o.put(5)
+        o.put(6)
+        self.run_worker(self._test_queue, o)
+        assert o.empty()
+        assert not o.full()
+
+    def test_joinable_queue(self):
+        self.test_queue("JoinableQueue")
+
+    @classmethod
+    def _test_list(cls, obj):
+        assert obj[0] == 5
+        assert obj.count(5) == 1
+        assert obj.index(5) == 0
+        obj.sort()
+        obj.reverse()
+        for x in obj:
+            pass
+        assert len(obj) == 1
+        assert obj.pop(0) == 5
+
+    def test_list(self):
+        o = self.manager.list()
+        o.append(5)
+        self.run_worker(self._test_list, o)
+        assert not o
+        self.assertEqual(len(o), 0)
+
+    @classmethod
+    def _test_dict(cls, obj):
+        assert len(obj) == 1
+        assert obj['foo'] == 5
+        assert obj.get('foo') == 5
+        assert list(obj.items()) == [('foo', 5)]
+        assert list(obj.keys()) == ['foo']
+        assert list(obj.values()) == [5]
+        assert obj.copy() == {'foo': 5}
+        assert obj.popitem() == ('foo', 5)
+
+    def test_dict(self):
+        o = self.manager.dict()
+        o['foo'] = 5
+        self.run_worker(self._test_dict, o)
+        assert not o
+        self.assertEqual(len(o), 0)
+
+    @classmethod
+    def _test_value(cls, obj):
+        assert obj.value == 1
+        assert obj.get() == 1
+        obj.set(2)
+
+    def test_value(self):
+        o = self.manager.Value('i', 1)
+        self.run_worker(self._test_value, o)
+        self.assertEqual(o.value, 2)
+        self.assertEqual(o.get(), 2)
+
+    @classmethod
+    def _test_array(cls, obj):
+        assert obj[0] == 0
+        assert obj[1] == 1
+        assert len(obj) == 2
+        assert list(obj) == [0, 1]
+
+    def test_array(self):
+        o = self.manager.Array('i', [0, 1])
+        self.run_worker(self._test_array, o)
+
+    @classmethod
+    def _test_namespace(cls, obj):
+        assert obj.x == 0
+        assert obj.y == 1
+
+    def test_namespace(self):
+        o = self.manager.Namespace()
+        o.x = 0
+        o.y = 1
+        self.run_worker(self._test_namespace, o)
+
+
+class TestNamedResource(unittest.TestCase):
+    @unittest.skipIf(sys.hexversion <= 0x30a05f0, "SemLock subclass")
+    def test_global_named_resource_spawn(self):
+        #
+        # gh-90549: Check that global named resources in main module
+        # will not leak by a subprocess, in spawn context.
+        #
+        testfn = os_helper.TESTFN
+        self.addCleanup(os_helper.unlink, testfn)
+        with open(testfn, 'w', encoding='utf-8') as f:
+            f.write(textwrap.dedent('''\
+                import multiprocess as mp
+
+                ctx = mp.get_context('spawn')
+
+                global_resource = ctx.Semaphore()
+
+                def submain(): pass
+
+                if __name__ == '__main__':
+                    p = ctx.Process(target=submain)
+                    p.start()
+                    p.join()
+            '''))
+        rc, out, err = test.support.script_helper.assert_python_ok(testfn, **ENV)
+        # on error, err = 'UserWarning: resource_tracker: There appear to
+        # be 1 leaked semaphore objects to clean up at shutdown'
+        self.assertEqual(err, b'')
+
+
+class MiscTestCase(unittest.TestCase):
+    def test__all__(self):
+        # Just make sure names in not_exported are excluded
+        support.check__all__(self, multiprocessing, extra=multiprocessing.__all__,
+                             not_exported=['SUBDEBUG', 'SUBWARNING',
+                                           'license', 'citation'])
+
+
+#
+# Mixins
+#
+
+class BaseMixin(object):
+    @classmethod
+    def setUpClass(cls):
+        cls.dangling = (multiprocessing.process._dangling.copy(),
+                        threading._dangling.copy())
+
+    @classmethod
+    def tearDownClass(cls):
+        # bpo-26762: Some multiprocessing objects like Pool create reference
+        # cycles. Trigger a garbage collection to break these cycles.
+        test.support.gc_collect()
+
+        processes = set(multiprocessing.process._dangling) - set(cls.dangling[0])
+        if processes:
+            test.support.environment_altered = True
+            support.print_warning(f'Dangling processes: {processes}')
+        processes = None
+
+        threads = set(threading._dangling) - set(cls.dangling[1])
+        if threads:
+            test.support.environment_altered = True
+            support.print_warning(f'Dangling threads: {threads}')
+        threads = None
+
+
+class ProcessesMixin(BaseMixin):
+    TYPE = 'processes'
+    Process = multiprocessing.Process
+    connection = multiprocessing.connection
+    current_process = staticmethod(multiprocessing.current_process)
+    parent_process = staticmethod(multiprocessing.parent_process)
+    active_children = staticmethod(multiprocessing.active_children)
+    Pool = staticmethod(multiprocessing.Pool)
+    Pipe = staticmethod(multiprocessing.Pipe)
+    Queue = staticmethod(multiprocessing.Queue)
+    JoinableQueue = staticmethod(multiprocessing.JoinableQueue)
+    Lock = staticmethod(multiprocessing.Lock)
+    RLock = staticmethod(multiprocessing.RLock)
+    Semaphore = staticmethod(multiprocessing.Semaphore)
+    BoundedSemaphore = staticmethod(multiprocessing.BoundedSemaphore)
+    Condition = staticmethod(multiprocessing.Condition)
+    Event = staticmethod(multiprocessing.Event)
+    Barrier = staticmethod(multiprocessing.Barrier)
+    Value = staticmethod(multiprocessing.Value)
+    Array = staticmethod(multiprocessing.Array)
+    RawValue = staticmethod(multiprocessing.RawValue)
+    RawArray = staticmethod(multiprocessing.RawArray)
+
+
+class ManagerMixin(BaseMixin):
+    TYPE = 'manager'
+    Process = multiprocessing.Process
+    Queue = property(operator.attrgetter('manager.Queue'))
+    JoinableQueue = property(operator.attrgetter('manager.JoinableQueue'))
+    Lock = property(operator.attrgetter('manager.Lock'))
+    RLock = property(operator.attrgetter('manager.RLock'))
+    Semaphore = property(operator.attrgetter('manager.Semaphore'))
+    BoundedSemaphore = property(operator.attrgetter('manager.BoundedSemaphore'))
+    Condition = property(operator.attrgetter('manager.Condition'))
+    Event = property(operator.attrgetter('manager.Event'))
+    Barrier = property(operator.attrgetter('manager.Barrier'))
+    Value = property(operator.attrgetter('manager.Value'))
+    Array = property(operator.attrgetter('manager.Array'))
+    list = property(operator.attrgetter('manager.list'))
+    dict = property(operator.attrgetter('manager.dict'))
+    Namespace = property(operator.attrgetter('manager.Namespace'))
+
+    @classmethod
+    def Pool(cls, *args, **kwds):
+        return cls.manager.Pool(*args, **kwds)
+
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.manager = multiprocessing.Manager()
+
+    @classmethod
+    def tearDownClass(cls):
+        # only the manager process should be returned by active_children()
+        # but this can take a bit on slow machines, so wait a few seconds
+        # if there are other children too (see #17395)
+        start_time = time.monotonic()
+        t = 0.01
+        while len(multiprocessing.active_children()) > 1:
+            time.sleep(t)
+            t *= 2
+            dt = time.monotonic() - start_time
+            if dt >= 5.0:
+                test.support.environment_altered = True
+                support.print_warning(f"multiprocess.Manager still has "
+                                      f"{multiprocessing.active_children()} "
+                                      f"active children after {dt} seconds")
+                break
+
+        gc.collect()                       # do garbage collection
+        if cls.manager._number_of_objects() != 0:
+            # This is not really an error since some tests do not
+            # ensure that all processes which hold a reference to a
+            # managed object have been joined.
+            test.support.environment_altered = True
+            support.print_warning('Shared objects which still exist '
+                                  'at manager shutdown:')
+            support.print_warning(cls.manager._debug_info())
+        cls.manager.shutdown()
+        cls.manager.join()
+        cls.manager = None
+
+        super().tearDownClass()
+
+
+class ThreadsMixin(BaseMixin):
+    TYPE = 'threads'
+    Process = multiprocessing.dummy.Process
+    connection = multiprocessing.dummy.connection
+    current_process = staticmethod(multiprocessing.dummy.current_process)
+    active_children = staticmethod(multiprocessing.dummy.active_children)
+    Pool = staticmethod(multiprocessing.dummy.Pool)
+    Pipe = staticmethod(multiprocessing.dummy.Pipe)
+    Queue = staticmethod(multiprocessing.dummy.Queue)
+    JoinableQueue = staticmethod(multiprocessing.dummy.JoinableQueue)
+    Lock = staticmethod(multiprocessing.dummy.Lock)
+    RLock = staticmethod(multiprocessing.dummy.RLock)
+    Semaphore = staticmethod(multiprocessing.dummy.Semaphore)
+    BoundedSemaphore = staticmethod(multiprocessing.dummy.BoundedSemaphore)
+    Condition = staticmethod(multiprocessing.dummy.Condition)
+    Event = staticmethod(multiprocessing.dummy.Event)
+    Barrier = staticmethod(multiprocessing.dummy.Barrier)
+    Value = staticmethod(multiprocessing.dummy.Value)
+    Array = staticmethod(multiprocessing.dummy.Array)
+
+#
+# Functions used to create test cases from the base ones in this module
+#
+
+def install_tests_in_module_dict(remote_globs, start_method):
+    __module__ = remote_globs['__name__']
+    local_globs = globals()
+    ALL_TYPES = {'processes', 'threads', 'manager'}
+
+    for name, base in local_globs.items():
+        if not isinstance(base, type):
+            continue
+        if issubclass(base, BaseTestCase):
+            if base is BaseTestCase:
+                continue
+            assert set(base.ALLOWED_TYPES) <= ALL_TYPES, base.ALLOWED_TYPES
+            for type_ in base.ALLOWED_TYPES:
+                newname = 'With' + type_.capitalize() + name[1:]
+                Mixin = local_globs[type_.capitalize() + 'Mixin']
+                class Temp(base, Mixin, unittest.TestCase):
+                    pass
+                if type_ == 'manager':
+                    Temp = hashlib_helper.requires_hashdigest('md5')(Temp)
+                Temp.__name__ = Temp.__qualname__ = newname
+                Temp.__module__ = __module__
+                remote_globs[newname] = Temp
+        elif issubclass(base, unittest.TestCase):
+            class Temp(base, object):
+                pass
+            Temp.__name__ = Temp.__qualname__ = name
+            Temp.__module__ = __module__
+            remote_globs[name] = Temp
+
+    dangling = [None, None]
+    old_start_method = [None]
+
+    def setUpModule():
+        multiprocessing.set_forkserver_preload(PRELOAD)
+        multiprocessing.process._cleanup()
+        dangling[0] = multiprocessing.process._dangling.copy()
+        dangling[1] = threading._dangling.copy()
+        old_start_method[0] = multiprocessing.get_start_method(allow_none=True)
+        try:
+            multiprocessing.set_start_method(start_method, force=True)
+        except ValueError:
+            raise unittest.SkipTest(start_method +
+                                    ' start method not supported')
+
+        if sys.platform.startswith("linux"):
+            try:
+                lock = multiprocessing.RLock()
+            except OSError:
+                raise unittest.SkipTest("OSError raises on RLock creation, "
+                                        "see issue 3111!")
+        check_enough_semaphores()
+        util.get_temp_dir()     # creates temp directory
+        multiprocessing.get_logger().setLevel(LOG_LEVEL)
+
+    def tearDownModule():
+        need_sleep = False
+
+        # bpo-26762: Some multiprocessing objects like Pool create reference
+        # cycles. Trigger a garbage collection to break these cycles.
+        test.support.gc_collect()
+
+        multiprocessing.set_start_method(old_start_method[0], force=True)
+        # pause a bit so we don't get warning about dangling threads/processes
+        processes = set(multiprocessing.process._dangling) - set(dangling[0])
+        if processes:
+            need_sleep = True
+            test.support.environment_altered = True
+            support.print_warning(f'Dangling processes: {processes}')
+        processes = None
+
+        threads = set(threading._dangling) - set(dangling[1])
+        if threads:
+            need_sleep = True
+            test.support.environment_altered = True
+            support.print_warning(f'Dangling threads: {threads}')
+        threads = None
+
+        # Sleep 500 ms to give time to child processes to complete.
+        if need_sleep:
+            time.sleep(0.5)
+
+        multiprocessing.util._cleanup_tests()
+
+    remote_globs['setUpModule'] = setUpModule
+    remote_globs['tearDownModule'] = tearDownModule
+
+
+@unittest.skipIf(not hasattr(_multiprocessing, 'SemLock'), 'SemLock not available')
+@unittest.skipIf(sys.platform != "linux", "Linux only")
+@unittest.skipIf(sys.hexversion <= 0x30a05f0, "SemLock subclass")
+class SemLockTests(unittest.TestCase):
+
+    def test_semlock_subclass(self):
+        class SemLock(_multiprocessing.SemLock):
+            pass
+        name = f'test_semlock_subclass-{os.getpid()}'
+        s = SemLock(1, 0, 10, name, False)
+        _multiprocessing.sem_unlink(name)