gtest_test_utils.py revision 1be2c9def7187e4e643c00a31dd9986395795d7d 
1#!/usr/bin/env python
2#
3# Copyright 2006, Google Inc.
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31
32"""Unit test utilities for Google C++ Testing Framework."""
33
34__author__ = 'wan@google.com (Zhanyong Wan)'
35
36import os
37import sys
38import unittest
39
40try:
41  import subprocess
42  _SUBPROCESS_MODULE_AVAILABLE = True
43except:
44  import popen2
45  _SUBPROCESS_MODULE_AVAILABLE = False
46
47
48# Initially maps a flag to its default value.  After
49# _ParseAndStripGTestFlags() is called, maps a flag to its actual
50# value.
51_flag_map = {'gtest_source_dir': os.path.dirname(sys.argv[0]),
52             'gtest_build_dir': os.path.dirname(sys.argv[0])}
53_gtest_flags_are_parsed = False
54
55
56def _ParseAndStripGTestFlags(argv):
57  """Parses and strips Google Test flags from argv.  This is idempotent."""
58
59  global _gtest_flags_are_parsed
60  if _gtest_flags_are_parsed:
61    return
62
63  _gtest_flags_are_parsed = True
64  for flag in _flag_map:
65    # The environment variable overrides the default value.
66    if flag.upper() in os.environ:
67      _flag_map[flag] = os.environ[flag.upper()]
68
69    # The command line flag overrides the environment variable.
70    i = 1  # Skips the program name.
71    while i < len(argv):
72      prefix = '--' + flag + '='
73      if argv[i].startswith(prefix):
74        _flag_map[flag] = argv[i][len(prefix):]
75        del argv[i]
76        break
77      else:
78        # We don't increment i in case we just found a --gtest_* flag
79        # and removed it from argv.
80        i += 1
81
82
83def GetFlag(flag):
84  """Returns the value of the given flag."""
85
86  # In case GetFlag() is called before Main(), we always call
87  # _ParseAndStripGTestFlags() here to make sure the --gtest_* flags
88  # are parsed.
89  _ParseAndStripGTestFlags(sys.argv)
90
91  return _flag_map[flag]
92
93
94def GetSourceDir():
95  """Returns the absolute path of the directory where the .py files are."""
96
97  return os.path.abspath(GetFlag('gtest_source_dir'))
98
99
100def GetBuildDir():
101  """Returns the absolute path of the directory where the test binaries are."""
102
103  return os.path.abspath(GetFlag('gtest_build_dir'))
104
105
106def GetExitStatus(exit_code):
107  """Returns the argument to exit(), or -1 if exit() wasn't called.
108
109  Args:
110    exit_code: the result value of os.system(command).
111  """
112
113  if os.name == 'nt':
114    # On Windows, os.WEXITSTATUS() doesn't work and os.system() returns
115    # the argument to exit() directly.
116    return exit_code
117  else:
118    # On Unix, os.WEXITSTATUS() must be used to extract the exit status
119    # from the result of os.system().
120    if os.WIFEXITED(exit_code):
121      return os.WEXITSTATUS(exit_code)
122    else:
123      return -1
124
125
126class Subprocess:
127  def __init__(self, command, working_dir=None):
128    """Changes into a specified directory, if provided, and executes a command.
129    Restores the old directory afterwards. Execution results are returned
130    via the following attributes:
131      terminated_by_sygnal   True iff the child process has been terminated
132                             by a signal.
133      signal                 Sygnal that terminated the child process.
134      exited                 True iff the child process exited normally.
135      exit_code              The code with which the child proces exited.
136      output                 Child process's stdout and stderr output
137                             combined in a string.
138
139    Args:
140      command: A command to run, in the form of sys.argv.
141      working_dir: A directory to change into.
142    """
143
144    # The subprocess module is the preferrable way of running programs
145    # since it is available and behaves consistently on all platforms,
146    # including Windows. But it is only available starting in python 2.4.
147    # In earlier python versions, we revert to the popen2 module, which is
148    # available in python 2.0 and later but doesn't provide required
149    # functionality (Popen4) under Windows. This allows us to support Mac
150    # OS X 10.4 Tiger, which has python 2.3 installed.
151    if _SUBPROCESS_MODULE_AVAILABLE:
152      p = subprocess.Popen(command,
153                           stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
154                           cwd=working_dir, universal_newlines=True)
155      # communicate returns a tuple with the file obect for the child's
156      # output.
157      self.output = p.communicate()[0]
158      self._return_code = p.returncode
159    else:
160      old_dir = os.getcwd()
161      try:
162        if working_dir is not None:
163          os.chdir(working_dir)
164        p = popen2.Popen4(command)
165        p.tochild.close()
166        self.output = p.fromchild.read()
167        ret_code = p.wait()
168      finally:
169        os.chdir(old_dir)
170      # Converts ret_code to match the semantics of
171      # subprocess.Popen.returncode.
172      if os.WIFSIGNALED(ret_code):
173        self._return_code = -os.WTERMSIG(ret_code)
174      else:  # os.WIFEXITED(ret_code) should return True here.
175        self._return_code = os.WEXITSTATUS(ret_code)
176
177    if self._return_code < 0:
178      self.terminated_by_signal = True
179      self.exited = False
180      self.signal = -self._return_code
181    else:
182      self.terminated_by_signal = False
183      self.exited = True
184      self.exit_code = self._return_code
185
186
187def Main():
188  """Runs the unit test."""
189
190  # We must call _ParseAndStripGTestFlags() before calling
191  # unittest.main().  Otherwise the latter will be confused by the
192  # --gtest_* flags.
193  _ParseAndStripGTestFlags(sys.argv)
194  unittest.main()
195