tools/chrome_remote_control/chrome_remote_control/system_stub.py

# Copyright (c) 2012 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Provides stubs for os, sys and subprocess for testing

This test allows one to test code that itself uses os, sys, and subprocess.
"""
import os as real_os
import subprocess as real_subprocess

class SysModuleStub(object):
  def __init__(self):
    self.platform = ''

class OSPathModuleStub(object):
  def __init__(self, os_module_stub):
    self._os_module_stub = os_module_stub

  def exists(self, path):
    return path in self._os_module_stub.files

  def join(self, *args):
    if self._os_module_stub.sys.platform.startswith('win'):
      tmp = real_os.path.join(*args)
      return tmp.replace('/', '\\')
    else:
      return real_os.path.join(*args)

  def dirname(self, filename): # pylint: disable=R0201
    return real_os.path.dirname(filename)

class OSModuleStub(object):
  def __init__(self, sys):
    self.sys = sys
    self.path = OSPathModuleStub(self)
    self.files = []
    self.display = ':0'
    self.local_app_data = None

  def getenv(self, name):
    if name == 'DISPLAY':
      return self.display
    if name == 'LOCALAPPDATA':
      return self.local_app_data
    raise Exception('Unsupported getenv')

class PopenStub(object):
  def __init__(self, communicate_result):
    self.communicate_result = communicate_result

  def communicate(self):
    return self.communicate_result

class SubprocessModuleStub(object):
  def __init__(self):
    self.Popen_hook = None
    self.Popen_result = None
    self.PIPE = real_subprocess.PIPE

  def Popen(self, *args, **kwargs):
    assert self.Popen_hook or self.Popen_result
    if self.Popen_hook:
      return self.Popen_hook(*args, **kwargs)
    else:
      return self.Popen_result