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