• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1# Protocol Buffers - Google's data interchange format
2# Copyright 2008 Google Inc.  All rights reserved.
3# https://developers.google.com/protocol-buffers/
4#
5# Redistribution and use in source and binary forms, with or without
6# modification, are permitted provided that the following conditions are
7# met:
8#
9#     * Redistributions of source code must retain the above copyright
10# notice, this list of conditions and the following disclaimer.
11#     * Redistributions in binary form must reproduce the above
12# copyright notice, this list of conditions and the following disclaimer
13# in the documentation and/or other materials provided with the
14# distribution.
15#     * Neither the name of Google Inc. nor the names of its
16# contributors may be used to endorse or promote products derived from
17# this software without specific prior written permission.
18#
19# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31"""A subclass of unittest.TestCase which checks for reference leaks.
32
33To use:
34- Use testing_refleak.BaseTestCase instead of unittest.TestCase
35- Configure and compile Python with --with-pydebug
36
37If sys.gettotalrefcount() is not available (because Python was built without
38the Py_DEBUG option), then this module is a no-op and tests will run normally.
39"""
40
41import copyreg
42import gc
43import sys
44import unittest
45
46
47class LocalTestResult(unittest.TestResult):
48  """A TestResult which forwards events to a parent object, except for Skips."""
49
50  def __init__(self, parent_result):
51    unittest.TestResult.__init__(self)
52    self.parent_result = parent_result
53
54  def addError(self, test, error):
55    self.parent_result.addError(test, error)
56
57  def addFailure(self, test, error):
58    self.parent_result.addFailure(test, error)
59
60  def addSkip(self, test, reason):
61    pass
62
63
64class ReferenceLeakCheckerMixin(object):
65  """A mixin class for TestCase, which checks reference counts."""
66
67  NB_RUNS = 3
68
69  def run(self, result=None):
70    # python_message.py registers all Message classes to some pickle global
71    # registry, which makes the classes immortal.
72    # We save a copy of this registry, and reset it before we could references.
73    self._saved_pickle_registry = copyreg.dispatch_table.copy()
74
75    # Run the test twice, to warm up the instance attributes.
76    super(ReferenceLeakCheckerMixin, self).run(result=result)
77    super(ReferenceLeakCheckerMixin, self).run(result=result)
78
79    oldrefcount = 0
80    local_result = LocalTestResult(result)
81
82    refcount_deltas = []
83    for _ in range(self.NB_RUNS):
84      oldrefcount = self._getRefcounts()
85      super(ReferenceLeakCheckerMixin, self).run(result=local_result)
86      newrefcount = self._getRefcounts()
87      refcount_deltas.append(newrefcount - oldrefcount)
88    print(refcount_deltas, self)
89
90    try:
91      self.assertEqual(refcount_deltas, [0] * self.NB_RUNS)
92    except Exception:  # pylint: disable=broad-except
93      result.addError(self, sys.exc_info())
94
95  def _getRefcounts(self):
96    copyreg.dispatch_table.clear()
97    copyreg.dispatch_table.update(self._saved_pickle_registry)
98    # It is sometimes necessary to gc.collect() multiple times, to ensure
99    # that all objects can be collected.
100    gc.collect()
101    gc.collect()
102    gc.collect()
103    return sys.gettotalrefcount()
104
105
106if hasattr(sys, 'gettotalrefcount'):
107
108  def TestCase(test_class):
109    new_bases = (ReferenceLeakCheckerMixin,) + test_class.__bases__
110    new_class = type(test_class)(
111        test_class.__name__, new_bases, dict(test_class.__dict__))
112    return new_class
113  SkipReferenceLeakChecker = unittest.skip
114
115else:
116  # When PyDEBUG is not enabled, run the tests normally.
117
118  def TestCase(test_class):
119    return test_class
120
121  def SkipReferenceLeakChecker(reason):
122    del reason  # Don't skip, so don't need a reason.
123    def Same(func):
124      return func
125    return Same
126