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| # Protocol Buffers - Google's data interchange format | |
| # Copyright 2008 Google Inc. All rights reserved. | |
| # | |
| # Use of this source code is governed by a BSD-style | |
| # license that can be found in the LICENSE file or at | |
| # https://developers.google.com/open-source/licenses/bsd | |
| """A subclass of unittest.TestCase which checks for reference leaks. | |
| To use: | |
| - Use testing_refleak.BaseTestCase instead of unittest.TestCase | |
| - Configure and compile Python with --with-pydebug | |
| If sys.gettotalrefcount() is not available (because Python was built without | |
| the Py_DEBUG option), then this module is a no-op and tests will run normally. | |
| """ | |
| import copyreg | |
| import gc | |
| import sys | |
| import unittest | |
| class LocalTestResult(unittest.TestResult): | |
| """A TestResult which forwards events to a parent object, except for Skips.""" | |
| def __init__(self, parent_result): | |
| unittest.TestResult.__init__(self) | |
| self.parent_result = parent_result | |
| def addError(self, test, error): | |
| self.parent_result.addError(test, error) | |
| def addFailure(self, test, error): | |
| self.parent_result.addFailure(test, error) | |
| def addSkip(self, test, reason): | |
| pass | |
| class ReferenceLeakCheckerMixin(object): | |
| """A mixin class for TestCase, which checks reference counts.""" | |
| NB_RUNS = 3 | |
| def run(self, result=None): | |
| testMethod = getattr(self, self._testMethodName) | |
| expecting_failure_method = getattr(testMethod, "__unittest_expecting_failure__", False) | |
| expecting_failure_class = getattr(self, "__unittest_expecting_failure__", False) | |
| if expecting_failure_class or expecting_failure_method: | |
| return | |
| # python_message.py registers all Message classes to some pickle global | |
| # registry, which makes the classes immortal. | |
| # We save a copy of this registry, and reset it before we could references. | |
| self._saved_pickle_registry = copyreg.dispatch_table.copy() | |
| # Run the test twice, to warm up the instance attributes. | |
| super(ReferenceLeakCheckerMixin, self).run(result=result) | |
| super(ReferenceLeakCheckerMixin, self).run(result=result) | |
| oldrefcount = 0 | |
| local_result = LocalTestResult(result) | |
| num_flakes = 0 | |
| refcount_deltas = [] | |
| while len(refcount_deltas) < self.NB_RUNS: | |
| oldrefcount = self._getRefcounts() | |
| super(ReferenceLeakCheckerMixin, self).run(result=local_result) | |
| newrefcount = self._getRefcounts() | |
| # If the GC was able to collect some objects after the call to run() that | |
| # it could not collect before the call, then the counts won't match. | |
| if newrefcount < oldrefcount and num_flakes < 2: | |
| # This result is (probably) a flake -- garbage collectors aren't very | |
| # predictable, but a lower ending refcount is the opposite of the | |
| # failure we are testing for. If the result is repeatable, then we will | |
| # eventually report it, but not after trying to eliminate it. | |
| num_flakes += 1 | |
| continue | |
| num_flakes = 0 | |
| refcount_deltas.append(newrefcount - oldrefcount) | |
| print(refcount_deltas, self) | |
| try: | |
| self.assertEqual(refcount_deltas, [0] * self.NB_RUNS) | |
| except Exception: # pylint: disable=broad-except | |
| result.addError(self, sys.exc_info()) | |
| def _getRefcounts(self): | |
| copyreg.dispatch_table.clear() | |
| copyreg.dispatch_table.update(self._saved_pickle_registry) | |
| # It is sometimes necessary to gc.collect() multiple times, to ensure | |
| # that all objects can be collected. | |
| gc.collect() | |
| gc.collect() | |
| gc.collect() | |
| return sys.gettotalrefcount() | |
| if hasattr(sys, 'gettotalrefcount'): | |
| def TestCase(test_class): | |
| new_bases = (ReferenceLeakCheckerMixin,) + test_class.__bases__ | |
| new_class = type(test_class)( | |
| test_class.__name__, new_bases, dict(test_class.__dict__)) | |
| return new_class | |
| SkipReferenceLeakChecker = unittest.skip | |
| else: | |
| # When PyDEBUG is not enabled, run the tests normally. | |
| def TestCase(test_class): | |
| return test_class | |
| def SkipReferenceLeakChecker(reason): | |
| del reason # Don't skip, so don't need a reason. | |
| def Same(func): | |
| return func | |
| return Same | |