[chrome_remote_control] Use monkey patching for stubs.

tools/chrome_remote_control/chrome_remote_control/desktop_browser_finder_unittest.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.
-import os as real_os
 import unittest
 
 from chrome_remote_control import browser_options
 from chrome_remote_control import desktop_browser_finder
 from chrome_remote_control.system_stub import *
 
 # This file verifies the logic for finding a browser instance on all platforms
 # at once. It does so by providing stubs for the OS/sys/subprocess primitives
 # that the underlying finding logic usually uses to locate a suitable browser.
 # We prefer this approach to having to run the same test on every platform on
 # which we want this code to work.
 
-class StubSubprocess(object):
-  def __init__(self):
-    self.call_hook = None
-
-  def call(self, *args, **kwargs):
-    assert self.call_hook
-    return self.call_hook(*args, **kwargs)
-
 class FindTestBase(unittest.TestCase):
   def setUp(self):
     self._options = browser_options.BrowserOptions()
     self._options.chrome_root = '../../../'
     self._sys_stub = SysModuleStub()
     self._os_stub = OSModuleStub(self._sys_stub)
-    self._subprocess_stub = StubSubprocess()
+    self._subprocess_stub = SubprocessModuleStub()

[nduca, 2012/09/20 04:18:30]

Where do you tear down?

[dtu, 2012/09/25 02:01:50]

Done.

 
   @property
   def _files(self):
     return self._os_stub.files
 
   def DoFindAll(self):
-    return desktop_browser_finder.FindAllAvailableBrowsers(self._options,
-        self._os_stub, self._sys_stub, self._subprocess_stub)
+    with Override(desktop_browser_finder,
+                  os=self._os_stub,

[nduca, 2012/09/20 04:18:30]

how about making override just create all the right things and override them in
setUp/tearDown, and thenwe do all the customizations of the stubs by mutating
the monkey patched forms? 

And how is Override getting into the namespace?

[dtu, 2012/09/25 02:01:50]

Done. Override is from system_stub.

+                  subprocess=self._subprocess_stub,
+                  sys=self._sys_stub):
+      return desktop_browser_finder.FindAllAvailableBrowsers(self._options)
 
   def DoFindAllTypes(self):
     browsers = self.DoFindAll()
     return [b.browser_type for b in browsers]
 
 def has_type(array, browser_type):
   return len([x for x in array if x.browser_type == browser_type]) != 0
 
 class OSXFindTest(FindTestBase):
   def setUp(self):
@@ skipping 93 matching lines @@
 
   def testFindAllWithExact(self):
     self._options.browser_executable = 'c:\\tmp\\chrome.exe'
     types = self.DoFindAllTypes()
     self.assertEquals(
         set(types),
         set(['exact',
              'debug', 'release',
              'content-shell-debug', 'content-shell-release',
              'system', 'canary']))