#!/usr/bin/env python

#

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"""Unit test utilities for Google C++ Testing Framework."""

__author__ = 'wan@google.com (Zhanyong Wan)'

import atexit

import os

import shutil

import sys

import tempfile

import unittest

_test_module = unittest

# Suppresses the 'Import not at the top of the file' lint complaint.

# pylint: disable-msg=C6204

try:

  import subprocess

  _SUBPROCESS_MODULE_AVAILABLE = True

except:

  import popen2

  _SUBPROCESS_MODULE_AVAILABLE = False

# pylint: enable-msg=C6204

GTEST_OUTPUT_VAR_NAME = 'GTEST_OUTPUT'

IS_WINDOWS = os.name == 'nt'

IS_CYGWIN = os.name == 'posix' and 'CYGWIN' in os.uname()[0]

# The environment variable for specifying the path to the premature-exit file.

PREMATURE_EXIT_FILE_ENV_VAR = 'TEST_PREMATURE_EXIT_FILE'

environ = os.environ.copy()

def SetEnvVar(env_var, value):

  """Sets/unsets an environment variable to a given value."""

  if value is not None:

    environ[env_var] = value

  elif env_var in environ:

    del environ[env_var]

# Here we expose a class from a particular module, depending on the

# environment. The comment suppresses the 'Invalid variable name' lint

# complaint.

TestCase = _test_module.TestCase  # pylint: disable-msg=C6409

# Initially maps a flag to its default value. After

# _ParseAndStripGTestFlags() is called, maps a flag to its actual value.

_flag_map = {'source_dir': os.path.dirname(sys.argv[0]),

             'build_dir': os.path.dirname(sys.argv[0])}

_gtest_flags_are_parsed = False

def _ParseAndStripGTestFlags(argv):

  """Parses and strips Google Test flags from argv.  This is idempotent."""

  # Suppresses the lint complaint about a global variable since we need it

  # here to maintain module-wide state.

  global _gtest_flags_are_parsed  # pylint: disable-msg=W0603

  if _gtest_flags_are_parsed:

    return

  _gtest_flags_are_parsed = True

  for flag in _flag_map:

    # The environment variable overrides the default value.

    if flag.upper() in os.environ:

      _flag_map[flag] = os.environ[flag.upper()]

    # The command line flag overrides the environment variable.

    i = 1  # Skips the program name.

    while i < len(argv):

      prefix = '--' + flag + '='

      if argv[i].startswith(prefix):

        _flag_map[flag] = argv[i][len(prefix):]

        del argv[i]

        break

      else:

        # We don't increment i in case we just found a --gtest_* flag

        # and removed it from argv.

        i += 1

def GetFlag(flag):

  """Returns the value of the given flag."""

  # In case GetFlag() is called before Main(), we always call

  # _ParseAndStripGTestFlags() here to make sure the --gtest_* flags

  # are parsed.

  _ParseAndStripGTestFlags(sys.argv)

  return _flag_map[flag]

def GetSourceDir():

  """Returns the absolute path of the directory where the .py files are."""

  return os.path.abspath(GetFlag('source_dir'))

def GetBuildDir():

  """Returns the absolute path of the directory where the test binaries are."""

  return os.path.abspath(GetFlag('build_dir'))

_temp_dir = None

def _RemoveTempDir():

  if _temp_dir:

    shutil.rmtree(_temp_dir, ignore_errors=True)

atexit.register(_RemoveTempDir)

def GetTempDir():

  """Returns a directory for temporary files."""

  global _temp_dir

  if not _temp_dir:

    _temp_dir = tempfile.mkdtemp()

  return _temp_dir

def GetTestExecutablePath(executable_name, build_dir=None):

  """Returns the absolute path of the test binary given its name.

  The function will print a message and abort the program if the resulting file

  doesn't exist.

  Args:

    executable_name: name of the test binary that the test script runs.

    build_dir:       directory where to look for executables, by default

                     the result of GetBuildDir().

  Returns:

    The absolute path of the test binary.

  """

  path = os.path.abspath(os.path.join(build_dir or GetBuildDir(),

                                      executable_name))

  if (IS_WINDOWS or IS_CYGWIN) and not path.endswith('.exe'):

    path += '.exe'

  if not os.path.exists(path):

    message = (

        'Unable to find the test binary "%s". Please make sure to provide\n'

        'a path to the binary via the --build_dir flag or the BUILD_DIR\n'

        'environment variable.' % path)

    sys.stdout.write(message)

    sys.exit(1)

  return path

def GetExitStatus(exit_code):

  """Returns the argument to exit(), or -1 if exit() wasn't called.

  Args:

    exit_code: the result value of os.system(command).

  """

  if os.name == 'nt':

    # On Windows, os.WEXITSTATUS() doesn't work and os.system() returns

    # the argument to exit() directly.

    return exit_code

  else:

    # On Unix, os.WEXITSTATUS() must be used to extract the exit status

    # from the result of os.system().

    if os.WIFEXITED(exit_code):

      return os.WEXITSTATUS(exit_code)

    else:

      return -1

class Subprocess:

  def __init__(self, command, working_dir=None, capture_stderr=True, env=None):

    """Changes into a specified directory, if provided, and executes a command.

    Restores the old directory afterwards.

    Args:

      command:        The command to run, in the form of sys.argv.

      working_dir:    The directory to change into.

      capture_stderr: Determines whether to capture stderr in the output member

                      or to discard it.

      env:            Dictionary with environment to pass to the subprocess.

    Returns:

      An object that represents outcome of the executed process. It has the

      following attributes:

        terminated_by_signal   True iff the child process has been terminated

                               by a signal.

        signal                 Sygnal that terminated the child process.

        exited                 True iff the child process exited normally.

        exit_code              The code with which the child process exited.

        output                 Child process's stdout and stderr output

                               combined in a string.

    """

    # The subprocess module is the preferrable way of running programs

    # since it is available and behaves consistently on all platforms,

    # including Windows. But it is only available starting in python 2.4.

    # In earlier python versions, we revert to the popen2 module, which is

    # available in python 2.0 and later but doesn't provide required

    # functionality (Popen4) under Windows. This allows us to support Mac

    # OS X 10.4 Tiger, which has python 2.3 installed.

    if _SUBPROCESS_MODULE_AVAILABLE:

      if capture_stderr:

        stderr = subprocess.STDOUT

      else:

        stderr = subprocess.PIPE

      p = subprocess.Popen(command,

                           stdout=subprocess.PIPE, stderr=stderr,

                           cwd=working_dir, universal_newlines=True, env=env)

      # communicate returns a tuple with the file obect for the child's

      # output.

      self.output = p.communicate()[0]

      self._return_code = p.returncode

    else:

      old_dir = os.getcwd()

      def _ReplaceEnvDict(dest, src):

        # Changes made by os.environ.clear are not inheritable by child

        # processes until Python 2.6. To produce inheritable changes we have

        # to delete environment items with the del statement.

        for key in dest.keys():

          del dest[key]

        dest.update(src)

      # When 'env' is not None, backup the environment variables and replace

      # them with the passed 'env'. When 'env' is None, we simply use the

      # current 'os.environ' for compatibility with the subprocess.Popen

      # semantics used above.

      if env is not None:

        old_environ = os.environ.copy()

        _ReplaceEnvDict(os.environ, env)

      try:

        if working_dir is not None:

          os.chdir(working_dir)

        if capture_stderr:

          p = popen2.Popen4(command)

        else:

          p = popen2.Popen3(command)

        p.tochild.close()

        self.output = p.fromchild.read()

        ret_code = p.wait()

      finally:

        os.chdir(old_dir)

        # Restore the old environment variables

        # if they were replaced.

        if env is not None:

          _ReplaceEnvDict(os.environ, old_environ)

      # Converts ret_code to match the semantics of

      # subprocess.Popen.returncode.

      if os.WIFSIGNALED(ret_code):

        self._return_code = -os.WTERMSIG(ret_code)

      else:  # os.WIFEXITED(ret_code) should return True here.

        self._return_code = os.WEXITSTATUS(ret_code)

    if self._return_code < 0:

      self.terminated_by_signal = True

      self.exited = False

      self.signal = -self._return_code

    else:

      self.terminated_by_signal = False

      self.exited = True

      self.exit_code = self._return_code

def Main():

  """Runs the unit test."""

  # We must call _ParseAndStripGTestFlags() before calling

  # unittest.main().  Otherwise the latter will be confused by the

  # --gtest_* flags.

  _ParseAndStripGTestFlags(sys.argv)

  # The tested binaries should not be writing XML output files unless the

  # script explicitly instructs them to.

  # TODO(vladl@google.com): Move this into Subprocess when we implement

  # passing environment into it as a parameter.

  if GTEST_OUTPUT_VAR_NAME in os.environ:

    del os.environ[GTEST_OUTPUT_VAR_NAME]

  _test_module.main()