Remove git lockfile flakiness on win (bot_update)

tests/bot_update_coverage_test.py

 #!/usr/bin/env python
 # Copyright (c) 2015 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 codecs
 import copy
 import json
 import os
+import subprocess
 import sys
 import unittest
 
 #import test_env  # pylint: disable=W0403,W0611
 
 sys.path.insert(0, os.path.join(
     os.path.dirname(os.path.dirname(os.path.abspath(__file__))),
     'recipe_modules', 'bot_update', 'resources'))
 sys.platform = 'linux2'  # For consistency, ya know?
 import bot_update
@@ skipping 135 matching lines @@
     if 'w' in mode:
       self.files[target] = FakeFile()
       return self.files[target]
     return self.files[target]
 
 
 def fake_git(*args, **kwargs):
   return bot_update.call('git', *args, **kwargs)
 
 
+class MockSubprocess():
+  def __init__(self):
+    self.calls = []
+
+  def call(self, command):
+    self.calls.append(command)
+    return 0
+
+
 class BotUpdateUnittests(unittest.TestCase):
   def setUp(self):
     self.filesystem = FakeFilesystem()
     self.call = MockedCall(self.filesystem)
     self.gclient = MockedGclientSync(self.filesystem)
     self.call.expect(('gclient', 'sync')).returns(self.gclient)
     self.old_call = getattr(bot_update, 'call')
     self.params = copy.deepcopy(DEFAULT_PARAMS)
     setattr(bot_update, 'call', self.call)
     setattr(bot_update, 'git', fake_git)
 
     self.old_os_cwd = os.getcwd
     setattr(os, 'getcwd', lambda: '/b/build/slave/foo/build')
 
     setattr(bot_update, 'open', self.filesystem.open)
     self.old_codecs_open = codecs.open
     setattr(codecs, 'open', self.filesystem.open)
 
+    self.subprocess = MockSubprocess()
+    self.old_sp_call = subprocess.call
+    setattr(subprocess, 'call', self.subprocess.call)
+
   def tearDown(self):
     setattr(bot_update, 'call', self.old_call)
     setattr(os, 'getcwd', self.old_os_cwd)
     delattr(bot_update, 'open')
     setattr(codecs, 'open', self.old_codecs_open)
+    delattr(subprocess, 'call')
+    setattr(subprocess, 'call', self.old_sp_call)
 
   def testBasic(self):
     bot_update.ensure_checkout(**self.params)
     return self.call.records
 
   def testBasicShallow(self):
     self.params['shallow'] = True
     bot_update.ensure_checkout(**self.params)
     return self.call.records
 
+  def testMaybeRemoveWinLockfile(self):
+    git_lockfile_err = '''
+        fatal: Unable to create 'E:/b/c/b/win/src/.git/index.lock': File exists.
+        '''
+    bot_update.maybe_remove_win_lockfile('win32', git_lockfile_err)
+    self.assertEqual(
+        self.subprocess.calls,
+        [['cmd.exe', '/c', 'del', '/f',
+          '/q', 'E:/b/c/b/win/src/.git/index.lock']])
+
 
 if __name__ == '__main__':
   unittest.main()