Improve presubmit_support.py handling of git checkout.

tests/presubmit_unittest.py

 #!/usr/bin/python
 # Copyright (c) 2010 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.
 
 """Unit tests for presubmit_support.py and presubmit_canned_checks.py."""
 
 # pylint is too confused.
 # pylint: disable=E1101,E1103,W0212,W0403
 
@@ skipping 578 matching lines @@
     self.assertEqual(['win', 'linux'],
                      presubmit.DoGetTrySlaves([filename, filename_linux],
                                               self.fake_root_dir, None, False,
                                               output))
 
   def testMain(self):
     # OptParser calls presubmit.os.path.exists and is a pain when mocked.
     self.UnMock(presubmit.os.path, 'exists')
     self.mox.StubOutWithMock(presubmit, 'DoPresubmitChecks')
     self.mox.StubOutWithMock(presubmit, 'ParseFiles')
+    presubmit.os.path.isdir(presubmit.os.path.join(self.fake_root_dir, '.svn')
+        ).AndReturn(False)
     presubmit.os.path.isdir(presubmit.os.path.join(self.fake_root_dir, '.git')
         ).AndReturn(False)
-    presubmit.os.path.isdir(presubmit.os.path.join(self.fake_root_dir, '.svn')
-        ).AndReturn(False)
-    #presubmit.ParseFiles([], None).AndReturn([])
+    presubmit.subprocess.call(
+        ['git', 'rev-parse', '--show-cdup'],
+        cwd=self.fake_root_dir,
+        stdout=presubmit.subprocess.PIPE).AndReturn(1)
     presubmit.DoPresubmitChecks(mox.IgnoreArg(), False, False,
                                 mox.IgnoreArg(),
                                 mox.IgnoreArg(),
                                 None, False).AndReturn(False)
     self.mox.ReplayAll()
 
     self.assertEquals(True,
                       presubmit.Main(['presubmit', '--root',
                                       self.fake_root_dir]))
 
@@ skipping 1145 matching lines @@
     results = presubmit_canned_checks.CheckBuildbotPendingBuilds(
         input_api, presubmit.OutputApi, 'uurl', 2, ('foo'))
     self.assertEquals(len(results), 1)
     self.assertEquals(results[0].__class__,
         presubmit.OutputApi.PresubmitNotifyResult)
 
 
 if __name__ == '__main__':
   import unittest
   unittest.main()