#!/usr/bin/env python
# Copyright 2017 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Runs all permutations of pairs of tests in a gtest binary to attempt to
detect state leakage between tests.

Example invocation:

gn gen out/asan --args='is_asan=true enable_nacl=false is_debug=false'
ninja -C out/asan base_unittests
tools/perry.py out/asan/base_unittests > perry.log &
tail -f perry.log

You might want to run it in `screen` as it'll take a while.
"""

from __future__ import print_function

import argparse
import os
import multiprocessing
import subprocess
import sys


def _GetTestList(path_to_binary):
  """Returns a set of full test names.

  Each test will be of the form "Case.Test". There will be a separate line
  for each combination of Case/Test (there are often multiple tests in each
  case).
  """
  raw_output = subprocess.check_output([path_to_binary, "--gtest_list_tests"])
  input_lines = raw_output.splitlines()

  # The format of the gtest_list_tests output is:
  # "Case1."
  # "  Test1  # <Optional extra stuff>"
  # "  Test2"
  # "Case2."
  # "  Test1"
  case_name = ''  # Includes trailing dot.
  test_set = set()
  for line in input_lines:
    if len(line) > 1:
      if '#' in line:
        line = line[:line.find('#')]
      if line[0] == ' ':
        # Indented means a test in previous case.
        test_set.add(case_name + line.strip())
      else:
        # New test case.
        case_name = line.strip()

  return test_set


def _CheckForFailure(data):
  test_binary, pair0, pair1 = data
  p = subprocess.Popen(
      [test_binary, '--gtest_repeat=5', '--gtest_shuffle',
       '--gtest_filter=' + pair0 + ':' + pair1],
      stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
  out, _ = p.communicate()
  if p.returncode != 0:
    return (pair0, pair1, out)
  return None


def _PrintStatus(i, total, failed):
  status = '%d of %d tested (%d failures)' % (i+1, total, failed)
  print('\r%s%s' % (status, '\x1B[K'), end=' ')
  sys.stdout.flush()


def main():
  parser = argparse.ArgumentParser(description="Find failing pairs of tests.")
  parser.add_argument('binary', help='Path to gtest binary or wrapper script.')
  args = parser.parse_args()
  print('Getting test list...')
  all_tests = _GetTestList(args.binary)
  permuted = [(args.binary, x, y) for x in all_tests for y in all_tests]

  failed = []
  pool = multiprocessing.Pool()
  total_count = len(permuted)
  for i, result in enumerate(pool.imap_unordered(
      _CheckForFailure, permuted, 1)):
    if result:
      print('\n--gtest_filter=%s:%s failed\n\n%s\n\n' % (result[0], result[1],
                                                         result[2]))
      failed.append(result)
    _PrintStatus(i, total_count, len(failed))

  pool.terminate()
  pool.join()

  if failed:
    print('Failed pairs:')
    for f in failed:
      print(f[0], f[1])

  return 0


if __name__ == '__main__':
  sys.exit(main())