#!/usr/bin/env python3
#
# Copyright 2013 The Flutter Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""
A top level harness to run all unit-tests in a specific engine build.
"""

from pathlib import Path

import argparse
import errno
import glob
import logging
import logging.handlers
import multiprocessing
import os
import re
import shutil
import subprocess
# Explicitly import the parts of sys that are needed. This is to avoid using
# sys.stdout and sys.stderr directly. Instead, only the logger defined below
# should be used for output.
from sys import exit as sys_exit, platform as sys_platform
import tempfile
import time
import typing
import xvfb

SCRIPT_DIR = os.path.dirname(os.path.realpath(__file__))
BUILDROOT_DIR = os.path.abspath(os.path.join(os.path.realpath(__file__), '..', '..', '..'))
OUT_DIR = os.path.join(BUILDROOT_DIR, 'out')
GOLDEN_DIR = os.path.join(BUILDROOT_DIR, 'flutter', 'testing', 'resources')
FONTS_DIR = os.path.join(BUILDROOT_DIR, 'flutter', 'third_party', 'txt', 'third_party', 'fonts')
ROBOTO_FONT_PATH = os.path.join(FONTS_DIR, 'Roboto-Regular.ttf')
FONT_SUBSET_DIR = os.path.join(BUILDROOT_DIR, 'flutter', 'tools', 'font_subset')

ENCODING = 'UTF-8'

LOG_FILE = os.path.join(OUT_DIR, 'run_tests.log')
logger = logging.getLogger(__name__)
console_logger_handler = logging.StreamHandler()
file_logger_handler = logging.FileHandler(LOG_FILE)


# Override print so that it uses the logger instead of stdout directly.
def print(*args, **kwargs):  # pylint: disable=redefined-builtin
  logger.info(*args, **kwargs)


def print_divider(char='='):
  logger.info('\n')
  for _ in range(4):
    logger.info(''.join([char for _ in range(80)]))
  logger.info('\n')


def is_asan(build_dir):
  with open(os.path.join(build_dir, 'args.gn')) as args:
    if 'is_asan = true' in args.read():
      return True

  return False


def run_cmd(
    cmd: typing.List[str],
    forbidden_output: typing.List[str] = None,
    expect_failure: bool = False,
    env: typing.Dict[str, str] = None,
    allowed_failure_output: typing.List[str] = None,
    **kwargs
) -> None:
  if forbidden_output is None:
    forbidden_output = []
  if allowed_failure_output is None:
    allowed_failure_output = []

  command_string = ' '.join(cmd)

  print_divider('>')
  logger.info('Running command "%s"', command_string)

  start_time = time.time()

  process = subprocess.Popen(
      cmd,
      stdout=subprocess.PIPE,
      stderr=subprocess.STDOUT,
      env=env,
      universal_newlines=True,
      **kwargs
  )
  output = ''

  for line in iter(process.stdout.readline, ''):
    output += line
    logger.info(line.rstrip())

  process.wait()
  end_time = time.time()

  if process.returncode != 0 and not expect_failure:
    print_divider('!')

    logger.error(
        'Failed Command:\n\n%s\n\nExit Code: %s\n\nOutput:\n%s', command_string, process.returncode,
        output
    )

    print_divider('!')

    allowed_failure = False
    for allowed_string in allowed_failure_output:
      if allowed_string in output:
        allowed_failure = True

    if not allowed_failure:
      raise RuntimeError('Command "%s" exited with code %s.' % (command_string, process.returncode))

  for forbidden_string in forbidden_output:
    if forbidden_string in output:
      raise RuntimeError(
          'command "%s" contained forbidden string "%s"' % (command_string, forbidden_string)
      )

  print_divider('<')
  logger.info('Command run successfully in %.2f seconds: %s', end_time - start_time, command_string)


def is_mac():
  return sys_platform == 'darwin'


def is_aarm64():
  assert is_mac()
  output = subprocess.check_output(['sysctl', 'machdep.cpu'])
  text = output.decode('utf-8')
  aarm64 = text.find('Apple') >= 0
  if not aarm64:
    assert text.find('GenuineIntel') >= 0
  return aarm64


def is_linux():
  return sys_platform.startswith('linux')


def is_windows():
  return sys_platform.startswith(('cygwin', 'win'))


def executable_suffix():
  return '.exe' if is_windows() else ''


def find_executable_path(path):
  if os.path.exists(path):
    return path

  if is_windows():
    exe_path = path + '.exe'
    if os.path.exists(exe_path):
      return exe_path

    bat_path = path + '.bat'
    if os.path.exists(bat_path):
      return bat_path

  raise Exception('Executable %s does not exist!' % path)


def build_engine_executable_command(
    build_dir, executable_name, flags=None, coverage=False, gtest=False
):
  if flags is None:
    flags = []

  unstripped_exe = os.path.join(build_dir, 'exe.unstripped', executable_name)
  # We cannot run the unstripped binaries directly when coverage is enabled.
  if is_linux() and os.path.exists(unstripped_exe) and not coverage:
    # Use unstripped executables in order to get better symbolized crash
    # stack traces on Linux.
    executable = unstripped_exe
  else:
    executable = find_executable_path(os.path.join(build_dir, executable_name))

  coverage_script = os.path.join(BUILDROOT_DIR, 'flutter', 'build', 'generate_coverage.py')

  if coverage:
    coverage_flags = [
        '-t', executable, '-o',
        os.path.join(build_dir, 'coverage', executable_name), '-f', 'html'
    ]
    updated_flags = ['--args=%s' % ' '.join(flags)]
    test_command = [coverage_script] + coverage_flags + updated_flags
  else:
    test_command = [executable] + flags
    if gtest:
      gtest_parallel = os.path.join(
          BUILDROOT_DIR, 'flutter', 'third_party', 'gtest-parallel', 'gtest-parallel'
      )
      test_command = ['python3', gtest_parallel] + test_command

  return test_command


def run_engine_executable( # pylint: disable=too-many-arguments
    build_dir,
    executable_name,
    executable_filter,
    flags=None,
    cwd=BUILDROOT_DIR,
    forbidden_output=None,
    allowed_failure_output=None,
    expect_failure=False,
    coverage=False,
    extra_env=None,
    gtest=False,
):
  if executable_filter is not None and executable_name not in executable_filter:
    logger.info('Skipping %s due to filter.', executable_name)
    return

  if flags is None:
    flags = []
  if forbidden_output is None:
    forbidden_output = []
  if allowed_failure_output is None:
    allowed_failure_output = []
  if extra_env is None:
    extra_env = {}

  unstripped_exe = os.path.join(build_dir, 'exe.unstripped', executable_name)
  env = os.environ.copy()
  if is_linux():
    env['LD_LIBRARY_PATH'] = build_dir
    env['VK_DRIVER_FILES'] = os.path.join(build_dir, 'vk_swiftshader_icd.json')
    if os.path.exists(unstripped_exe):
      unstripped_vulkan = os.path.join(build_dir, 'lib.unstripped', 'libvulkan.so.1')
      if os.path.exists(unstripped_vulkan):
        vulkan_path = unstripped_vulkan
      else:
        vulkan_path = os.path.join(build_dir, 'libvulkan.so.1')
      try:
        os.symlink(vulkan_path, os.path.join(build_dir, 'exe.unstripped', 'libvulkan.so.1'))
      except OSError as err:
        if err.errno == errno.EEXIST:
          pass
        else:
          raise
  elif is_mac():
    env['DYLD_LIBRARY_PATH'] = build_dir
  else:
    env['PATH'] = build_dir + ':' + env['PATH']

  logger.info('Running %s in %s', executable_name, cwd)

  test_command = build_engine_executable_command(
      build_dir,
      executable_name,
      flags=flags,
      coverage=coverage,
      gtest=gtest,
  )

  env['FLUTTER_BUILD_DIRECTORY'] = build_dir
  for key, value in extra_env.items():
    env[key] = value

  try:
    run_cmd(
        test_command,
        cwd=cwd,
        forbidden_output=forbidden_output,
        expect_failure=expect_failure,
        env=env,
        allowed_failure_output=allowed_failure_output,
    )
  except:
    # The LUCI environment may provide a variable containing a directory path
    # for additional output files that will be uploaded to cloud storage.
    # If the command generated a core dump, then run a script to analyze
    # the dump and output a report that will be uploaded.
    luci_test_outputs_path = os.environ.get('FLUTTER_TEST_OUTPUTS_DIR')
    core_path = os.path.join(cwd, 'core')
    if luci_test_outputs_path and os.path.exists(core_path) and os.path.exists(unstripped_exe):
      dump_path = os.path.join(
          luci_test_outputs_path, '%s_%s.txt' % (executable_name, sys_platform)
      )
      logger.error('Writing core dump analysis to %s', dump_path)
      subprocess.call([
          os.path.join(BUILDROOT_DIR, 'flutter', 'testing', 'analyze_core_dump.sh'),
          BUILDROOT_DIR,
          unstripped_exe,
          core_path,
          dump_path,
      ])
      os.unlink(core_path)
    raise


class EngineExecutableTask():  # pylint: disable=too-many-instance-attributes

  def __init__( # pylint: disable=too-many-arguments
      self,
      build_dir,
      executable_name,
      executable_filter,
      flags=None,
      cwd=BUILDROOT_DIR,
      forbidden_output=None,
      allowed_failure_output=None,
      expect_failure=False,
      coverage=False,
      extra_env=None,
  ):
    self.build_dir = build_dir
    self.executable_name = executable_name
    self.executable_filter = executable_filter
    self.flags = flags
    self.cwd = cwd
    self.forbidden_output = forbidden_output
    self.allowed_failure_output = allowed_failure_output
    self.expect_failure = expect_failure
    self.coverage = coverage
    self.extra_env = extra_env

  def __call__(self, *args):
    run_engine_executable(
        self.build_dir,
        self.executable_name,
        self.executable_filter,
        flags=self.flags,
        cwd=self.cwd,
        forbidden_output=self.forbidden_output,
        allowed_failure_output=self.allowed_failure_output,
        expect_failure=self.expect_failure,
        coverage=self.coverage,
        extra_env=self.extra_env,
    )

  def __str__(self):
    command = build_engine_executable_command(
        self.build_dir, self.executable_name, flags=self.flags, coverage=self.coverage
    )
    return ' '.join(command)


shuffle_flags = [
    '--gtest_repeat=2',
    '--gtest_shuffle',
]


def run_cc_tests(build_dir, executable_filter, coverage, capture_core_dump):
  logger.info('Running Engine Unit-tests.')

  if capture_core_dump and is_linux():
    import resource  # pylint: disable=import-outside-toplevel
    resource.setrlimit(resource.RLIMIT_CORE, (resource.RLIM_INFINITY, resource.RLIM_INFINITY))

  repeat_flags = [
      '--repeat=2',
  ]

  def make_test(name, flags=None, extra_env=None):
    if flags is None:
      flags = repeat_flags
    if extra_env is None:
      extra_env = {}
    return (name, flags, extra_env)

  unittests = [
      make_test('client_wrapper_glfw_unittests'),
      make_test('client_wrapper_unittests'),
      make_test('common_cpp_core_unittests'),
      make_test('common_cpp_unittests'),
      make_test('dart_plugin_registrant_unittests'),
      make_test('display_list_rendertests'),
      make_test('display_list_unittests'),
      make_test('embedder_a11y_unittests'),
      make_test('embedder_proctable_unittests'),
      make_test('embedder_unittests'),
      make_test('fml_unittests'),
      make_test('fml_arc_unittests'),
      make_test('no_dart_plugin_registrant_unittests'),
      make_test('runtime_unittests'),
      make_test('testing_unittests'),
      make_test('tonic_unittests'),
      # The image release unit test can take a while on slow machines.
      make_test('ui_unittests', flags=repeat_flags + ['--timeout=90']),
  ]

  if not is_windows():
    unittests += [
        # https://github.com/google/googletest/issues/2490
        make_test('android_external_view_embedder_unittests'),
        make_test('jni_unittests'),
        make_test('platform_view_android_delegate_unittests'),
        # https://github.com/flutter/flutter/issues/36295
        make_test('shell_unittests'),
    ]

  if is_windows():
    unittests += [
        # The accessibility library only supports Mac and Windows.
        make_test('accessibility_unittests'),
        make_test('client_wrapper_windows_unittests'),
        make_test('flutter_windows_unittests'),
    ]

  # These unit-tests are Objective-C and can only run on Darwin.
  if is_mac():
    unittests += [
        # The accessibility library only supports Mac and Windows.
        make_test('accessibility_unittests'),
        make_test('availability_version_check_unittests'),
        make_test('framework_common_unittests'),
        make_test('spring_animation_unittests'),
        make_test('gpu_surface_metal_unittests'),
    ]

  if is_linux():
    flow_flags = [
        '--golden-dir=%s' % GOLDEN_DIR,
        '--font-file=%s' % ROBOTO_FONT_PATH,
    ]
    icu_flags = ['--icu-data-file-path=%s' % os.path.join(build_dir, 'icudtl.dat')]
    unittests += [
        make_test('flow_unittests', flags=repeat_flags + ['--'] + flow_flags),
        make_test('flutter_glfw_unittests'),
        make_test('flutter_linux_unittests', extra_env={'G_DEBUG': 'fatal-criticals'}),
        # https://github.com/flutter/flutter/issues/36296
        make_test('txt_unittests', flags=repeat_flags + ['--'] + icu_flags),
    ]
  else:
    flow_flags = ['--gtest_filter=-PerformanceOverlayLayer.Gold']
    unittests += [
        make_test('flow_unittests', flags=repeat_flags + flow_flags),
    ]

  build_name = os.path.basename(build_dir)
  try:
    if is_linux():
      xvfb.start_virtual_x(build_name, build_dir)
    for test, flags, extra_env in unittests:
      run_engine_executable(
          build_dir,
          test,
          executable_filter,
          flags,
          coverage=coverage,
          extra_env=extra_env,
          gtest=True
      )
  finally:
    if is_linux():
      xvfb.stop_virtual_x(build_name)

  if is_mac():
    # flutter_desktop_darwin_unittests uses global state that isn't handled
    # correctly by gtest-parallel.
    # https://github.com/flutter/flutter/issues/104789
    if not os.path.basename(build_dir).startswith('host_debug'):
      # Test is disabled for flaking in debug runs:
      # https://github.com/flutter/flutter/issues/127441
      run_engine_executable(
          build_dir,
          'flutter_desktop_darwin_unittests',
          executable_filter,
          shuffle_flags,
          coverage=coverage
      )
    extra_env = {
        # pylint: disable=line-too-long
        # See https://developer.apple.com/documentation/metal/diagnosing_metal_programming_issues_early?language=objc
        'MTL_SHADER_VALIDATION': '1',  # Enables all shader validation tests.
        'MTL_SHADER_VALIDATION_GLOBAL_MEMORY':
            '1',  # Validates accesses to device and constant memory.
        'MTL_SHADER_VALIDATION_THREADGROUP_MEMORY':
            '1',  # Validates accesses to threadgroup memory.
        'MTL_SHADER_VALIDATION_TEXTURE_USAGE':
            '1',  # Validates that texture references are not nil.
        # Note: built from //third_party/swiftshader
        'VK_ICD_FILENAMES': os.path.join(build_dir, 'vk_swiftshader_icd.json'),
        # Note: built from //third_party/vulkan_validation_layers:vulkan_gen_json_files
        # and //third_party/vulkan_validation_layers.
        'VK_LAYER_PATH': os.path.join(build_dir, 'vulkan-data'),
        'VK_INSTANCE_LAYERS': 'VK_LAYER_KHRONOS_validation',
    }
    if is_aarm64():
      extra_env.update({
          'METAL_DEBUG_ERROR_MODE': '0',  # Enables metal validation.
          'METAL_DEVICE_WRAPPER_TYPE': '1',  # Enables metal validation.
      })
    mac_impeller_unittests_flags = shuffle_flags + [
        '--enable_vulkan_validation',
        '--gtest_filter=-*OpenGLES'  # These are covered in the golden tests.
    ]
    # Impeller tests are only supported on macOS for now.
    run_engine_executable(
        build_dir,
        'impeller_unittests',
        executable_filter,
        mac_impeller_unittests_flags,
        coverage=coverage,
        extra_env=extra_env,
        # TODO(https://github.com/flutter/flutter/issues/123733): Remove this allowlist.
        # See also https://github.com/flutter/flutter/issues/114872.
        allowed_failure_output=[
            '[MTLCompiler createVertexStageAndLinkPipelineWithFragment:',
            '[MTLCompiler pipelineStateWithVariant:',
        ]
    )

    # Run one interactive Vulkan test with validation enabled.
    #
    # TODO(matanlurey): https://github.com/flutter/flutter/issues/134852; enable
    # more of the suite, and ideally we'd like to use Skia gold and take screen
    # shots as well.
    run_engine_executable(
        build_dir,
        'impeller_unittests',
        executable_filter,
        shuffle_flags + [
            '--enable_vulkan_validation',
            '--enable_playground',
            '--playground_timeout_ms=4000',
            '--gtest_filter="*ColorWheel/Vulkan"',
        ],
        coverage=coverage,
        extra_env=extra_env,
    )

    # Run the Flutter GPU test suite.
    run_engine_executable(
        build_dir,
        'impeller_dart_unittests',
        executable_filter,
        shuffle_flags + [
            '--enable_vulkan_validation',
            # TODO(https://github.com/flutter/flutter/issues/142642): Remove this.
            '--gtest_filter=-*OpenGLES',
        ],
        coverage=coverage,
        extra_env=extra_env,
    )


def run_engine_benchmarks(build_dir, executable_filter):
  logger.info('Running Engine Benchmarks.')

  icu_flags = ['--icu-data-file-path=%s' % os.path.join(build_dir, 'icudtl.dat')]

  run_engine_executable(build_dir, 'shell_benchmarks', executable_filter, icu_flags)

  run_engine_executable(build_dir, 'fml_benchmarks', executable_filter, icu_flags)

  run_engine_executable(build_dir, 'ui_benchmarks', executable_filter, icu_flags)

  run_engine_executable(build_dir, 'display_list_builder_benchmarks', executable_filter, icu_flags)

  run_engine_executable(build_dir, 'geometry_benchmarks', executable_filter, icu_flags)

  run_engine_executable(build_dir, 'canvas_benchmarks', executable_filter, icu_flags)

  if is_linux():
    run_engine_executable(build_dir, 'txt_benchmarks', executable_filter, icu_flags)


class FlutterTesterOptions():

  def __init__(
      self,
      multithreaded=False,
      enable_impeller=False,
      enable_observatory=False,
      expect_failure=False
  ):
    self.multithreaded = multithreaded
    self.enable_impeller = enable_impeller
    self.enable_observatory = enable_observatory
    self.expect_failure = expect_failure

  def apply_args(self, command_args):
    if not self.enable_observatory:
      command_args.append('--disable-observatory')

    if self.enable_impeller:
      command_args += ['--enable-impeller']
    else:
      command_args += ['--no-enable-impeller']

    if self.multithreaded:
      command_args.insert(0, '--force-multithreading')

  def threading_description(self):
    if self.multithreaded:
      return 'multithreaded'
    return 'single-threaded'

  def impeller_enabled(self):
    if self.enable_impeller:
      return 'impeller swiftshader'
    return 'skia software'


def gather_dart_test(build_dir, dart_file, options):
  kernel_file_name = os.path.basename(dart_file) + '.dill'
  kernel_file_output = os.path.join(build_dir, 'gen', kernel_file_name)
  error_message = "%s doesn't exist. Please run the build that populates %s" % (
      kernel_file_output, build_dir
  )
  assert os.path.isfile(kernel_file_output), error_message

  command_args = []

  options.apply_args(command_args)

  dart_file_contents = open(dart_file, 'r')
  custom_options = re.findall('// FlutterTesterOptions=(.*)', dart_file_contents.read())
  dart_file_contents.close()
  command_args.extend(custom_options)

  command_args += [
      '--use-test-fonts',
      '--icu-data-file-path=%s' % os.path.join(build_dir, 'icudtl.dat'),
      '--flutter-assets-dir=%s' % os.path.join(build_dir, 'gen', 'flutter', 'lib', 'ui', 'assets'),
      '--disable-asset-fonts',
      kernel_file_output,
  ]

  tester_name = 'flutter_tester'
  logger.info(
      "Running test '%s' using '%s' (%s, %s)", kernel_file_name, tester_name,
      options.threading_description(), options.impeller_enabled()
  )
  forbidden_output = [] if 'unopt' in build_dir or options.expect_failure else ['[ERROR']
  return EngineExecutableTask(
      build_dir,
      tester_name,
      None,
      command_args,
      forbidden_output=forbidden_output,
      expect_failure=options.expect_failure,
  )


def ensure_ios_tests_are_built(ios_out_dir):
  """Builds the engine variant and the test dylib containing the XCTests"""
  tmp_out_dir = os.path.join(OUT_DIR, ios_out_dir)
  ios_test_lib = os.path.join(tmp_out_dir, 'libios_test_flutter.dylib')
  message = []
  message.append('gn --ios --unoptimized --runtime-mode=debug --no-lto --simulator')
  message.append('ninja -C %s ios_test_flutter' % ios_out_dir)
  final_message = "%s or %s doesn't exist. Please run the following commands: \n%s" % (
      ios_out_dir, ios_test_lib, '\n'.join(message)
  )
  assert os.path.exists(tmp_out_dir) and os.path.exists(ios_test_lib), final_message


def assert_expected_xcode_version():
  """Checks that the user has a version of Xcode installed"""
  version_output = subprocess.check_output(['xcodebuild', '-version'])
  # TODO ricardoamador: remove this check when python 2 is deprecated.
  version_output = version_output if isinstance(version_output,
                                                str) else version_output.decode(ENCODING)
  version_output = version_output.strip()
  match = re.match(r'Xcode (\d+)', version_output)
  message = 'Xcode must be installed to run the iOS embedding unit tests'
  assert match, message


def java_home():
  script_path = os.path.dirname(os.path.realpath(__file__))
  if is_mac():
    return os.path.join(
        script_path, '..', '..', 'third_party', 'java', 'openjdk', 'Contents', 'Home'
    )
  return os.path.join(script_path, '..', '..', 'third_party', 'java', 'openjdk')


def java_bin():
  return os.path.join(java_home(), 'bin', 'java.exe' if is_windows() else 'java')


def run_java_tests(executable_filter, android_variant='android_debug_unopt'):
  """Runs the Java JUnit unit tests for the Android embedding"""
  test_runner_dir = os.path.join(
      BUILDROOT_DIR, 'flutter', 'shell', 'platform', 'android', 'test_runner'
  )
  gradle_bin = os.path.join(
      BUILDROOT_DIR, 'third_party', 'gradle', 'bin', 'gradle.bat' if is_windows() else 'gradle'
  )
  flutter_jar = os.path.join(OUT_DIR, android_variant, 'flutter.jar')
  android_home = os.path.join(BUILDROOT_DIR, 'third_party', 'android_tools', 'sdk')
  build_dir = os.path.join(OUT_DIR, android_variant, 'robolectric_tests', 'build')
  gradle_cache_dir = os.path.join(OUT_DIR, android_variant, 'robolectric_tests', '.gradle')

  test_class = executable_filter if executable_filter else '*'
  command = [
      gradle_bin,
      '-Pflutter_jar=%s' % flutter_jar,
      '-Pbuild_dir=%s' % build_dir,
      'testDebugUnitTest',
      '--tests=%s' % test_class,
      '--rerun-tasks',
      '--no-daemon',
      '--project-cache-dir=%s' % gradle_cache_dir,
      '--gradle-user-home=%s' % gradle_cache_dir,
  ]

  env = dict(os.environ, ANDROID_HOME=android_home, JAVA_HOME=java_home())
  run_cmd(command, cwd=test_runner_dir, env=env)


def run_android_tests(android_variant='android_debug_unopt', adb_path=None):
  test_runner_name = 'flutter_shell_native_unittests'
  tests_path = os.path.join(OUT_DIR, android_variant, test_runner_name)
  remote_path = '/data/local/tmp'
  remote_tests_path = os.path.join(remote_path, test_runner_name)
  if adb_path is None:
    adb_path = 'adb'
  run_cmd([adb_path, 'push', tests_path, remote_path], cwd=BUILDROOT_DIR)
  run_cmd([adb_path, 'shell', remote_tests_path])

  systrace_test = os.path.join(BUILDROOT_DIR, 'flutter', 'testing', 'android_systrace_test.py')
  scenario_apk = os.path.join(OUT_DIR, android_variant, 'firebase_apks', 'scenario_app.apk')
  run_cmd([
      systrace_test, '--adb-path', adb_path, '--apk-path', scenario_apk, '--package-name',
      'dev.flutter.scenarios', '--activity-name', '.PlatformViewsActivity'
  ])


def run_objc_tests(ios_variant='ios_debug_sim_unopt', test_filter=None):
  """Runs Objective-C XCTest unit tests for the iOS embedding"""
  assert_expected_xcode_version()
  ios_out_dir = os.path.join(OUT_DIR, ios_variant)
  ensure_ios_tests_are_built(ios_out_dir)

  new_simulator_name = 'IosUnitTestsSimulator'

  # Delete simulators with this name in case any were leaked
  # from another test run.
  delete_simulator(new_simulator_name)

  create_simulator = [
      'xcrun '
      'simctl '
      'create '
      '%s com.apple.CoreSimulator.SimDeviceType.iPhone-11' % new_simulator_name
  ]
  run_cmd(create_simulator, shell=True)

  try:
    ios_unit_test_dir = os.path.join(BUILDROOT_DIR, 'flutter', 'testing', 'ios', 'IosUnitTests')

    with tempfile.TemporaryDirectory(suffix='ios_embedding_xcresult') as result_bundle_temp:
      result_bundle_path = os.path.join(result_bundle_temp, 'ios_embedding')

      # Avoid using xcpretty unless the following can be addressed:
      # - Make sure all relevant failure output is printed on a failure.
      # - Make sure that a failing exit code is set for CI.
      # See https://github.com/flutter/flutter/issues/63742
      test_command = [
          'xcodebuild '
          '-sdk iphonesimulator '
          '-scheme IosUnitTests '
          '-resultBundlePath ' + result_bundle_path + ' '
          '-destination name=' + new_simulator_name + ' '
          'test '
          'FLUTTER_ENGINE=' + ios_variant
      ]
      if test_filter is not None:
        test_command[0] = test_command[0] + ' -only-testing:%s' % test_filter
      try:
        run_cmd(test_command, cwd=ios_unit_test_dir, shell=True)

      except:
        # The LUCI environment may provide a variable containing a directory path
        # for additional output files that will be uploaded to cloud storage.
        # Upload the xcresult when the tests fail.
        luci_test_outputs_path = os.environ.get('FLUTTER_TEST_OUTPUTS_DIR')
        xcresult_bundle = os.path.join(result_bundle_temp, 'ios_embedding.xcresult')
        if luci_test_outputs_path and os.path.exists(xcresult_bundle):
          dump_path = os.path.join(luci_test_outputs_path, 'ios_embedding.xcresult')
          # xcresults contain many little files. Archive the bundle before upload.
          shutil.make_archive(dump_path, 'zip', root_dir=xcresult_bundle)
        raise

  finally:
    delete_simulator(new_simulator_name)


def delete_simulator(simulator_name):
  # Will delete all simulators with this name.
  command = [
      'xcrun',
      'simctl',
      'delete',
      simulator_name,
  ]
  # Let this fail if the simulator was never created.
  run_cmd(command, expect_failure=True)


def gather_dart_tests(build_dir, test_filter):
  dart_tests_dir = os.path.join(
      BUILDROOT_DIR,
      'flutter',
      'testing',
      'dart',
  )

  # Now that we have the Sky packages at the hardcoded location, run `dart pub get`.
  run_engine_executable(
      build_dir,
      os.path.join('dart-sdk', 'bin', 'dart'),
      None,
      flags=['pub', 'get', '--offline'],
      cwd=dart_tests_dir,
  )

  dart_observatory_tests = glob.glob('%s/observatory/*_test.dart' % dart_tests_dir)
  dart_tests = glob.glob('%s/*_test.dart' % dart_tests_dir)

  if 'release' not in build_dir:
    for dart_test_file in dart_observatory_tests:
      if test_filter is not None and os.path.basename(dart_test_file) not in test_filter:
        logger.info("Skipping '%s' due to filter.", dart_test_file)
      else:
        logger.info("Gathering dart test '%s' with observatory enabled", dart_test_file)
        for multithreaded in [False, True]:
          for enable_impeller in [False, True]:
            yield gather_dart_test(
                build_dir, dart_test_file,
                FlutterTesterOptions(
                    multithreaded=multithreaded,
                    enable_impeller=enable_impeller,
                    enable_observatory=True
                )
            )

  for dart_test_file in dart_tests:
    if test_filter is not None and os.path.basename(dart_test_file) not in test_filter:
      logger.info("Skipping '%s' due to filter.", dart_test_file)
    else:
      logger.info("Gathering dart test '%s'", dart_test_file)
      for multithreaded in [False, True]:
        for enable_impeller in [False, True]:
          yield gather_dart_test(
              build_dir, dart_test_file,
              FlutterTesterOptions(multithreaded=multithreaded, enable_impeller=enable_impeller)
          )


def gather_dart_smoke_test(build_dir, test_filter):
  smoke_test = os.path.join(
      BUILDROOT_DIR,
      'flutter',
      'testing',
      'smoke_test_failure',
      'fail_test.dart',
  )
  if test_filter is not None and os.path.basename(smoke_test) not in test_filter:
    logger.info("Skipping '%s' due to filter.", smoke_test)
  else:
    yield gather_dart_test(
        build_dir, smoke_test, FlutterTesterOptions(multithreaded=True, expect_failure=True)
    )
    yield gather_dart_test(
        build_dir, smoke_test, FlutterTesterOptions(multithreaded=False, expect_failure=True)
    )


def gather_dart_package_tests(build_dir, package_path, extra_opts):
  dart_tests = glob.glob('%s/test/*_test.dart' % package_path)
  if not dart_tests:
    raise Exception('No tests found for Dart package at %s' % package_path)
  for dart_test_file in dart_tests:
    opts = ['--disable-dart-dev', dart_test_file] + extra_opts
    yield EngineExecutableTask(
        build_dir, os.path.join('dart-sdk', 'bin', 'dart'), None, flags=opts, cwd=package_path
    )


# Returns a list of Dart packages to test.
#
# The first element of each tuple in the returned list is the path to the Dart
# package to test. It is assumed that the packages follow the convention that
# tests are named as '*_test.dart', and reside under a directory called 'test'.
#
# The second element of each tuple is a list of additional command line
# arguments to pass to each of the packages tests.
def build_dart_host_test_list(build_dir):
  dart_host_tests = [
      (
          os.path.join('flutter', 'ci'),
          [os.path.join(BUILDROOT_DIR, 'flutter')],
      ),
      (
          os.path.join('flutter', 'flutter_frontend_server'),
          [
              build_dir,
              os.path.join(build_dir, 'gen', 'frontend_server.dart.snapshot'),
              os.path.join(build_dir, 'flutter_patched_sdk')
          ],
      ),
      (os.path.join('flutter', 'testing', 'litetest'), []),
      (os.path.join('flutter', 'testing', 'skia_gold_client'), []),
      (os.path.join('flutter', 'testing', 'scenario_app'), []),
      (
          os.path.join('flutter', 'tools', 'api_check'),
          [os.path.join(BUILDROOT_DIR, 'flutter')],
      ),
      (os.path.join('flutter', 'tools', 'build_bucket_golden_scraper'), []),
      (os.path.join('flutter', 'tools', 'clang_tidy'), []),
      (
          os.path.join('flutter', 'tools', 'const_finder'),
          [
              os.path.join(build_dir, 'gen', 'frontend_server.dart.snapshot'),
              os.path.join(build_dir, 'flutter_patched_sdk'),
              os.path.join(build_dir, 'dart-sdk', 'lib', 'libraries.json'),
          ],
      ),
      (os.path.join('flutter', 'tools', 'dir_contents_diff'), []),
      (os.path.join('flutter', 'tools', 'engine_tool'), []),
      (os.path.join('flutter', 'tools', 'githooks'), []),
      (os.path.join('flutter', 'tools', 'header_guard_check'), []),
      (os.path.join('flutter', 'tools', 'pkg', 'engine_build_configs'), []),
      (os.path.join('flutter', 'tools', 'pkg', 'engine_repo_tools'), []),
      (os.path.join('flutter', 'tools', 'pkg', 'git_repo_tools'), []),
  ]
  if not is_asan(build_dir):
    dart_host_tests += [
        (os.path.join('flutter', 'tools', 'path_ops', 'dart'), []),
    ]

  return dart_host_tests


def run_benchmark_tests(build_dir):
  test_dir = os.path.join(BUILDROOT_DIR, 'flutter', 'testing', 'benchmark')
  dart_tests = glob.glob('%s/test/*_test.dart' % test_dir)
  for dart_test_file in dart_tests:
    opts = ['--disable-dart-dev', dart_test_file]
    run_engine_executable(
        build_dir, os.path.join('dart-sdk', 'bin', 'dart'), None, flags=opts, cwd=test_dir
    )


def worker_init(queue, level):
  queue_handler = logging.handlers.QueueHandler(queue)
  log = logging.getLogger(__name__)
  log.setLevel(logging.INFO)
  queue_handler.setLevel(level)
  log.addHandler(queue_handler)


def run_engine_tasks_in_parallel(tasks):
  # Work around a bug in Python.
  #
  # The multiprocessing package relies on the win32 WaitForMultipleObjects()
  # call, which supports waiting on a maximum of MAXIMUM_WAIT_OBJECTS (defined
  # by Windows to be 64) handles, processes in this case. To avoid hitting
  # this, we limit ourselves to 60 handles (since there are a couple extra
  # processes launched for the queue reader and thread wakeup reader).
  #
  # See: https://bugs.python.org/issue26903
  max_processes = multiprocessing.cpu_count()
  if sys_platform.startswith(('cygwin', 'win')) and max_processes > 60:
    max_processes = 60

  queue = multiprocessing.Queue()
  queue_listener = logging.handlers.QueueListener(
      queue,
      console_logger_handler,
      file_logger_handler,
      respect_handler_level=True,
  )
  queue_listener.start()

  failures = []
  try:
    with multiprocessing.Pool(max_processes, worker_init,
                              [queue, logger.getEffectiveLevel()]) as pool:
      async_results = [(t, pool.apply_async(t, ())) for t in tasks]
      for task, async_result in async_results:
        try:
          async_result.get()
        except Exception as exn:  # pylint: disable=broad-except
          failures += [(task, exn)]
  finally:
    queue_listener.stop()

  if len(failures) > 0:
    logger.error('The following commands failed:')
    for task, exn in failures:
      logger.error('%s\n  %s\n\n', str(task), str(exn))
    return False

  return True


class DirectoryChange():
  """
  A scoped change in the CWD.
  """
  old_cwd: str = ''
  new_cwd: str = ''

  def __init__(self, new_cwd: str):
    self.new_cwd = new_cwd

  def __enter__(self):
    self.old_cwd = os.getcwd()
    os.chdir(self.new_cwd)

  def __exit__(self, exception_type, exception_value, exception_traceback):
    os.chdir(self.old_cwd)


def run_impeller_golden_tests(build_dir: str):
  """
  Executes the impeller golden image tests from in the `variant` build.
  """
  tests_path: str = os.path.join(build_dir, 'impeller_golden_tests')
  if not os.path.exists(tests_path):
    raise Exception(
        'Cannot find the "impeller_golden_tests" executable in "%s". You may need to build it.' %
        (build_dir)
    )
  harvester_path: Path = Path(SCRIPT_DIR).parent.joinpath('tools'
                                                         ).joinpath('golden_tests_harvester')
  with tempfile.TemporaryDirectory(prefix='impeller_golden') as temp_dir:
    run_cmd([tests_path, f'--working_dir={temp_dir}'], cwd=build_dir)
    dart_bin = os.path.join(build_dir, 'dart-sdk', 'bin', 'dart')
    golden_path = os.path.join('testing', 'impeller_golden_tests_output.txt')
    script_path = os.path.join('tools', 'dir_contents_diff', 'bin', 'dir_contents_diff.dart')
    diff_result = subprocess.run(
        f'{dart_bin} run {script_path} {golden_path} {temp_dir}',
        check=False,
        shell=True,
        stdout=subprocess.PIPE,
        cwd=os.path.join(BUILDROOT_DIR, 'flutter')
    )
    if diff_result.returncode != 0:
      print_divider('<')
      print(diff_result.stdout.decode())
      raise RuntimeError('impeller_golden_tests diff failure')

    with DirectoryChange(harvester_path):
      bin_path = Path('.').joinpath('bin').joinpath('golden_tests_harvester.dart')
      run_cmd([dart_bin, 'run', str(bin_path), temp_dir])


def main():
  parser = argparse.ArgumentParser(
      description="""
In order to learn the details of running tests in the engine, please consult the
Flutter Wiki page on the subject: https://github.com/flutter/flutter/wiki/Testing-the-engine
"""
  )
  all_types = [
      'engine',
      'dart',
      'dart-host',
      'benchmarks',
      'java',
      'android',
      'objc',
      'font-subset',
      'impeller-golden',
  ]

  parser.add_argument(
      '--variant',
      dest='variant',
      action='store',
      default='host_debug_unopt',
      help='The engine build variant to run the tests for.'
  )
  parser.add_argument(
      '--type',
      type=str,
      default='all',
      help='A list of test types, default is "all" (equivalent to "%s")' % (','.join(all_types))
  )
  parser.add_argument(
      '--engine-filter', type=str, default='', help='A list of engine test executables to run.'
  )
  parser.add_argument(
      '--dart-filter',
      type=str,
      default='',
      help='A list of Dart test scripts to run in flutter_tester.'
  )
  parser.add_argument(
      '--dart-host-filter',
      type=str,
      default='',
      help='A list of Dart test scripts to run with the Dart CLI.'
  )
  parser.add_argument(
      '--java-filter',
      type=str,
      default='',
      help='A single Java test class to run (example: "io.flutter.SmokeTest")'
  )
  parser.add_argument(
      '--android-variant',
      dest='android_variant',
      action='store',
      default='android_debug_unopt',
      help='The engine build variant to run java or android tests for'
  )
  parser.add_argument(
      '--ios-variant',
      dest='ios_variant',
      action='store',
      default='ios_debug_sim_unopt',
      help='The engine build variant to run objective-c tests for'
  )
  parser.add_argument(
      '--verbose-dart-snapshot',
      dest='verbose_dart_snapshot',
      action='store_true',
      default=False,
      help='Show extra dart snapshot logging.'
  )
  parser.add_argument(
      '--objc-filter',
      type=str,
      default=None,
      help=(
          'Filter parameter for which objc tests to run '
          '(example: "IosUnitTestsTests/SemanticsObjectTest/testShouldTriggerAnnouncement")'
      )
  )
  parser.add_argument(
      '--coverage',
      action='store_true',
      default=None,
      help='Generate coverage reports for each unit test framework run.'
  )
  parser.add_argument(
      '--engine-capture-core-dump',
      dest='engine_capture_core_dump',
      action='store_true',
      default=False,
      help='Capture core dumps from crashes of engine tests.'
  )
  parser.add_argument(
      '--use-sanitizer-suppressions',
      dest='sanitizer_suppressions',
      action='store_true',
      default=False,
      help='Provide the sanitizer suppressions lists to the via environment to the tests.'
  )
  parser.add_argument(
      '--adb-path',
      dest='adb_path',
      action='store',
      default=None,
      help='Provide the path of adb used for android tests. By default it looks on $PATH.'
  )
  parser.add_argument(
      '--quiet',
      dest='quiet',
      action='store_true',
      default=False,
      help='Only emit output when there is an error.'
  )
  parser.add_argument(
      '--logs-dir',
      dest='logs_dir',
      type=str,
      help='The directory that verbose logs will be copied to in --quiet mode.',
  )

  args = parser.parse_args()

  logger.addHandler(console_logger_handler)
  logger.addHandler(file_logger_handler)
  logger.setLevel(logging.INFO)
  if args.quiet:
    file_logger_handler.setLevel(logging.INFO)
    console_logger_handler.setLevel(logging.WARNING)
  else:
    console_logger_handler.setLevel(logging.INFO)

  if args.type == 'all':
    types = all_types
  else:
    types = args.type.split(',')

  build_dir = os.path.join(OUT_DIR, args.variant)
  if args.type != 'java' and args.type != 'android':
    assert os.path.exists(build_dir), 'Build variant directory %s does not exist!' % build_dir

  if args.sanitizer_suppressions:
    assert is_linux() or is_mac(
    ), 'The sanitizer suppressions flag is only supported on Linux and Mac.'
    file_dir = os.path.dirname(os.path.abspath(__file__))
    command = [
        'env', '-i', 'bash', '-c',
        'source {}/sanitizer_suppressions.sh >/dev/null && env'.format(file_dir)
    ]
    process = subprocess.Popen(command, stdout=subprocess.PIPE)
    for line in process.stdout:
      key, _, value = line.decode('utf8').strip().partition('=')
      os.environ[key] = value
    process.communicate()  # Avoid pipe deadlock while waiting for termination.

  success = True

  engine_filter = args.engine_filter.split(',') if args.engine_filter else None
  if 'engine' in types:
    run_cc_tests(build_dir, engine_filter, args.coverage, args.engine_capture_core_dump)

  # Use this type to exclusively run impeller tests.
  if 'impeller' in types:
    build_name = args.variant
    try:
      xvfb.start_virtual_x(build_name, build_dir)
      run_engine_executable(
          build_dir, 'impeller_unittests', engine_filter, shuffle_flags, coverage=args.coverage
      )
    finally:
      xvfb.stop_virtual_x(build_name)

  if 'dart' in types:
    dart_filter = args.dart_filter.split(',') if args.dart_filter else None
    tasks = list(gather_dart_smoke_test(build_dir, dart_filter))
    tasks += list(gather_dart_tests(build_dir, dart_filter))
    success = success and run_engine_tasks_in_parallel(tasks)

  if 'dart-host' in types:
    dart_filter = args.dart_host_filter.split(',') if args.dart_host_filter else None
    dart_host_packages = build_dart_host_test_list(build_dir)
    tasks = []
    for dart_host_package, extra_opts in dart_host_packages:
      if dart_filter is None or dart_host_package in dart_filter:
        tasks += list(
            gather_dart_package_tests(
                build_dir,
                os.path.join(BUILDROOT_DIR, dart_host_package),
                extra_opts,
            )
        )

    success = success and run_engine_tasks_in_parallel(tasks)

  if 'java' in types:
    assert not is_windows(), "Android engine files can't be compiled on Windows."
    java_filter = args.java_filter
    if ',' in java_filter or '*' in java_filter:
      logger.wraning(
          'Can only filter JUnit4 tests by single entire class name, '
          'eg "io.flutter.SmokeTest". Ignoring filter=' + java_filter
      )
      java_filter = None
    run_java_tests(java_filter, args.android_variant)

  if 'android' in types:
    assert not is_windows(), "Android engine files can't be compiled on Windows."
    run_android_tests(args.android_variant, args.adb_path)

  if 'objc' in types:
    assert is_mac(), 'iOS embedding tests can only be run on macOS.'
    run_objc_tests(args.ios_variant, args.objc_filter)

  # https://github.com/flutter/flutter/issues/36300
  if 'benchmarks' in types and not is_windows():
    run_benchmark_tests(build_dir)
    run_engine_benchmarks(build_dir, engine_filter)

  variants_to_skip = ['host_release', 'host_profile']
  if ('engine' in types or 'font-subset' in types) and args.variant not in variants_to_skip:
    cmd = ['python3', 'test.py', '--variant', args.variant]
    if 'arm64' in args.variant:
      cmd += ['--target-cpu', 'arm64']
    run_cmd(cmd, cwd=FONT_SUBSET_DIR)

  if 'impeller-golden' in types:
    run_impeller_golden_tests(build_dir)

  if args.quiet and args.logs_dir:
    shutil.copy(LOG_FILE, os.path.join(args.logs_dir, 'run_tests.log'))

  return 0 if success else 1


if __name__ == '__main__':
  sys_exit(main())