1#!/usr/bin/env python
2#
3# Copyright 2006, Google Inc.
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31
32"""Unit test for Google Test's break-on-failure mode.
33
34A user can ask Google Test to seg-fault when an assertion fails, using
35either the GTEST_BREAK_ON_FAILURE environment variable or the
36--gtest_break_on_failure flag.  This script tests such functionality
37by invoking gtest_break_on_failure_unittest_ (a program written with
38Google Test) with different environments and command line flags.
39"""
40
41__author__ = 'wan@google.com (Zhanyong Wan)'
42
43import gtest_test_utils
44import os
45import sys
46
47
48# Constants.
49
50IS_WINDOWS = os.name == 'nt'
51
52# The environment variable for enabling/disabling the break-on-failure mode.
53BREAK_ON_FAILURE_ENV_VAR = 'GTEST_BREAK_ON_FAILURE'
54
55# The command line flag for enabling/disabling the break-on-failure mode.
56BREAK_ON_FAILURE_FLAG = 'gtest_break_on_failure'
57
58# The environment variable for enabling/disabling the throw-on-failure mode.
59THROW_ON_FAILURE_ENV_VAR = 'GTEST_THROW_ON_FAILURE'
60
61# The environment variable for enabling/disabling the catch-exceptions mode.
62CATCH_EXCEPTIONS_ENV_VAR = 'GTEST_CATCH_EXCEPTIONS'
63
64# Path to the gtest_break_on_failure_unittest_ program.
65EXE_PATH = gtest_test_utils.GetTestExecutablePath(
66    'gtest_break_on_failure_unittest_')
67
68
69# Utilities.
70
71
72def SetEnvVar(env_var, value):
73  """Sets an environment variable to a given value; unsets it when the
74  given value is None.
75  """
76
77  if value is not None:
78    os.environ[env_var] = value
79  elif env_var in os.environ:
80    del os.environ[env_var]
81
82
83def Run(command):
84  """Runs a command; returns 1 if it was killed by a signal, or 0 otherwise."""
85
86  p = gtest_test_utils.Subprocess(command)
87  if p.terminated_by_signal:
88    return 1
89  else:
90    return 0
91
92
93# The tests.
94
95
96class GTestBreakOnFailureUnitTest(gtest_test_utils.TestCase):
97  """Tests using the GTEST_BREAK_ON_FAILURE environment variable or
98  the --gtest_break_on_failure flag to turn assertion failures into
99  segmentation faults.
100  """
101
102  def RunAndVerify(self, env_var_value, flag_value, expect_seg_fault):
103    """Runs gtest_break_on_failure_unittest_ and verifies that it does
104    (or does not) have a seg-fault.
105
106    Args:
107      env_var_value:    value of the GTEST_BREAK_ON_FAILURE environment
108                        variable; None if the variable should be unset.
109      flag_value:       value of the --gtest_break_on_failure flag;
110                        None if the flag should not be present.
111      expect_seg_fault: 1 if the program is expected to generate a seg-fault;
112                        0 otherwise.
113    """
114
115    SetEnvVar(BREAK_ON_FAILURE_ENV_VAR, env_var_value)
116
117    if env_var_value is None:
118      env_var_value_msg = ' is not set'
119    else:
120      env_var_value_msg = '=' + env_var_value
121
122    if flag_value is None:
123      flag = ''
124    elif flag_value == '0':
125      flag = '--%s=0' % BREAK_ON_FAILURE_FLAG
126    else:
127      flag = '--%s' % BREAK_ON_FAILURE_FLAG
128
129    command = [EXE_PATH]
130    if flag:
131      command.append(flag)
132
133    if expect_seg_fault:
134      should_or_not = 'should'
135    else:
136      should_or_not = 'should not'
137
138    has_seg_fault = Run(command)
139
140    SetEnvVar(BREAK_ON_FAILURE_ENV_VAR, None)
141
142    msg = ('when %s%s, an assertion failure in "%s" %s cause a seg-fault.' %
143           (BREAK_ON_FAILURE_ENV_VAR, env_var_value_msg, ' '.join(command),
144            should_or_not))
145    self.assert_(has_seg_fault == expect_seg_fault, msg)
146
147  def testDefaultBehavior(self):
148    """Tests the behavior of the default mode."""
149
150    self.RunAndVerify(env_var_value=None,
151                      flag_value=None,
152                      expect_seg_fault=0)
153
154  def testEnvVar(self):
155    """Tests using the GTEST_BREAK_ON_FAILURE environment variable."""
156
157    self.RunAndVerify(env_var_value='0',
158                      flag_value=None,
159                      expect_seg_fault=0)
160    self.RunAndVerify(env_var_value='1',
161                      flag_value=None,
162                      expect_seg_fault=1)
163
164  def testFlag(self):
165    """Tests using the --gtest_break_on_failure flag."""
166
167    self.RunAndVerify(env_var_value=None,
168                      flag_value='0',
169                      expect_seg_fault=0)
170    self.RunAndVerify(env_var_value=None,
171                      flag_value='1',
172                      expect_seg_fault=1)
173
174  def testFlagOverridesEnvVar(self):
175    """Tests that the flag overrides the environment variable."""
176
177    self.RunAndVerify(env_var_value='0',
178                      flag_value='0',
179                      expect_seg_fault=0)
180    self.RunAndVerify(env_var_value='0',
181                      flag_value='1',
182                      expect_seg_fault=1)
183    self.RunAndVerify(env_var_value='1',
184                      flag_value='0',
185                      expect_seg_fault=0)
186    self.RunAndVerify(env_var_value='1',
187                      flag_value='1',
188                      expect_seg_fault=1)
189
190  def testBreakOnFailureOverridesThrowOnFailure(self):
191    """Tests that gtest_break_on_failure overrides gtest_throw_on_failure."""
192
193    SetEnvVar(THROW_ON_FAILURE_ENV_VAR, '1')
194    try:
195      self.RunAndVerify(env_var_value=None,
196                        flag_value='1',
197                        expect_seg_fault=1)
198    finally:
199      SetEnvVar(THROW_ON_FAILURE_ENV_VAR, None)
200
201  if IS_WINDOWS:
202    def testCatchExceptionsDoesNotInterfere(self):
203      """Tests that gtest_catch_exceptions doesn't interfere."""
204
205      SetEnvVar(CATCH_EXCEPTIONS_ENV_VAR, '1')
206      try:
207        self.RunAndVerify(env_var_value='1',
208                          flag_value='1',
209                          expect_seg_fault=1)
210      finally:
211        SetEnvVar(CATCH_EXCEPTIONS_ENV_VAR, None)
212
213
214if __name__ == '__main__':
215  gtest_test_utils.Main()
216