#!/usr/bin/env python
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"""Unit test for Google Test test filters.

A user can specify which test(s) in a Google Test program to run via either
the GTEST_FILTER environment variable or the --gtest_filter flag.
This script tests such functionality by invoking
gtest_filter_unittest_ (a program written with Google Test) with different
environments and command line flags.
"""

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

import gtest_test_utils
import os
import re
import sys
import unittest

# Constants.

# The environment variable for specifying the test filters.
FILTER_ENV_VAR = 'GTEST_FILTER'

# The command line flag for specifying the test filters.
FILTER_FLAG = 'gtest_filter'

# Command to run the gtest_filter_unittest_ program.
COMMAND = os.path.join(gtest_test_utils.GetBuildDir(),
                       'gtest_filter_unittest_')

# Regex for parsing test case names from Google Test's output.
TEST_CASE_REGEX = re.compile(r'^\[\-+\] \d+ test.* from (\w+)')

# Regex for parsing test names from Google Test's output.
TEST_REGEX = re.compile(r'^\[\s*RUN\s*\].*\.(\w+)')

# Full names of all tests in gtest_filter_unittests_.
ALL_TESTS = [
    'FooTest.Abc',
    'FooTest.Xyz',

    'BarTest.Test1',
    'BarTest.Test2',
    'BarTest.Test3',

    'BazTest.Test1',
    'BazTest.TestA',
    'BazTest.TestB',
    ]


# Utilities.


def SetEnvVar(env_var, value):
  """Sets the env variable to 'value'; unsets it when 'value' is None."""

  if value is not None:
    os.environ[env_var] = value
  elif env_var in os.environ:
    del os.environ[env_var]


def Run(command):
  """Runs a Google Test program and returns a list of full names of the
  tests that were run.
  """

  stdout_file = os.popen(command, 'r')
  tests_run = []
  test_case = ''
  test = ''
  for line in stdout_file:
    match = TEST_CASE_REGEX.match(line)
    if match is not None:
      test_case = match.group(1)
    else:
      match = TEST_REGEX.match(line)
      if match is not None:
        test = match.group(1)
        tests_run += [test_case + '.' + test]
  stdout_file.close()
  return tests_run


# The unit test.


class GTestFilterUnitTest(unittest.TestCase):
  """Tests using the GTEST_FILTER environment variable or the
  --gtest_filter flag to filter tests.
  """

  # Utilities.

  def AssertSetEqual(self, lhs, rhs):
    """Asserts that two sets are equal."""

    for elem in lhs:
      self.assert_(elem in rhs, '%s in %s' % (elem, rhs))

    for elem in rhs:
      self.assert_(elem in lhs, '%s in %s' % (elem, lhs))

  def RunAndVerify(self, gtest_filter, tests_to_run):
    """Runs gtest_flag_unittest_ with the given filter, and verifies
    that the right set of tests were run.
    """

    # First, tests using GTEST_FILTER.

    SetEnvVar(FILTER_ENV_VAR, gtest_filter)
    tests_run = Run(COMMAND)
    SetEnvVar(FILTER_ENV_VAR, None)

    self.AssertSetEqual(tests_run, tests_to_run)

    # Next, tests using --gtest_filter.

    if gtest_filter is None:
      command = COMMAND
    else:
      command = '%s --%s=%s' % (COMMAND, FILTER_FLAG, gtest_filter)

    tests_run = Run(command)
    self.AssertSetEqual(tests_run, tests_to_run)

  def testDefaultBehavior(self):
    """Tests the behavior of not specifying the filter."""

    self.RunAndVerify(None, ALL_TESTS)

  def testEmptyFilter(self):
    """Tests an empty filter."""

    self.RunAndVerify('', [])

  def testBadFilter(self):
    """Tests a filter that matches nothing."""

    self.RunAndVerify('BadFilter', [])

  def testFullName(self):
    """Tests filtering by full name."""

    self.RunAndVerify('FooTest.Xyz', ['FooTest.Xyz'])

  def testUniversalFilters(self):
    """Tests filters that match everything."""

    self.RunAndVerify('*', ALL_TESTS)
    self.RunAndVerify('*.*', ALL_TESTS)

  def testFilterByTestCase(self):
    """Tests filtering by test case name."""

    self.RunAndVerify('FooTest.*', ['FooTest.Abc', 'FooTest.Xyz'])

  def testFilterByTest(self):
    """Tests filtering by test name."""

    self.RunAndVerify('*.Test1', ['BarTest.Test1', 'BazTest.Test1'])

  def testWildcardInTestCaseName(self):
    """Tests using wildcard in the test case name."""

    self.RunAndVerify('*a*.*', [
        'BarTest.Test1',
        'BarTest.Test2',
        'BarTest.Test3',

        'BazTest.Test1',
        'BazTest.TestA',
        'BazTest.TestB',
        ])

  def testWildcardInTestName(self):
    """Tests using wildcard in the test name."""

    self.RunAndVerify('*.*A*', ['FooTest.Abc', 'BazTest.TestA'])

  def testFilterWithoutDot(self):
    """Tests a filter that has no '.' in it."""

    self.RunAndVerify('*z*', [
        'FooTest.Xyz',

        'BazTest.Test1',
        'BazTest.TestA',
        'BazTest.TestB',
        ])

  def testTwoPatterns(self):
    """Tests filters that consist of two patterns."""

    self.RunAndVerify('Foo*.*:*A*', [
        'FooTest.Abc',
        'FooTest.Xyz',

        'BazTest.TestA',
        ])

    # An empty pattern + a non-empty one
    self.RunAndVerify(':*A*', ['FooTest.Abc', 'BazTest.TestA'])

  def testThreePatterns(self):
    """Tests filters that consist of three patterns."""

    self.RunAndVerify('*oo*:*A*:*1', [
        'FooTest.Abc',
        'FooTest.Xyz',

        'BarTest.Test1',

        'BazTest.Test1',
        'BazTest.TestA',
        ])

    # The 2nd pattern is empty.
    self.RunAndVerify('*oo*::*1', [
        'FooTest.Abc',
        'FooTest.Xyz',

        'BarTest.Test1',

        'BazTest.Test1',
        ])

    # The last 2 patterns are empty.
    self.RunAndVerify('*oo*::', [
        'FooTest.Abc',
        'FooTest.Xyz',
        ])

  def testNegativeFilters(self):
    self.RunAndVerify('*-FooTest.Abc', [
        'FooTest.Xyz',

        'BarTest.Test1',
        'BarTest.Test2',
        'BarTest.Test3',

        'BazTest.Test1',
        'BazTest.TestA',
        'BazTest.TestB',
        ])

    self.RunAndVerify('*-FooTest.Abc:BazTest.*', [
        'FooTest.Xyz',

        'BarTest.Test1',
        'BarTest.Test2',
        'BarTest.Test3',
        ])

    self.RunAndVerify('BarTest.*-BarTest.Test1', [
        'BarTest.Test2',
        'BarTest.Test3',
        ])

    # Tests without leading '*'.
    self.RunAndVerify('-FooTest.Abc:FooTest.Xyz', [
        'BarTest.Test1',
        'BarTest.Test2',
        'BarTest.Test3',

        'BazTest.Test1',
        'BazTest.TestA',
        'BazTest.TestB',
        ])

  def testFlagOverridesEnvVar(self):
    """Tests that the --gtest_filter flag overrides the GTEST_FILTER
    environment variable."""

    SetEnvVar(FILTER_ENV_VAR, 'Foo*')
    command = '%s --%s=%s' % (COMMAND, FILTER_FLAG, '*1')
    tests_run = Run(command)
    SetEnvVar(FILTER_ENV_VAR, None)

    self.AssertSetEqual(tests_run, ['BarTest.Test1', 'BazTest.Test1'])


if __name__ == '__main__':
  gtest_test_utils.Main()