[SCM tests] Don't forget to change back to original cwd.

Tools/Scripts/webkitpy/common/checkout/scm/scm_unittest.py

 # Copyright (C) 2009 Google Inc. All rights reserved.
 # Copyright (C) 2009 Apple Inc. All rights reserved.
 # Copyright (C) 2011 Daniel Bates (dbates@intudata.com). All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #    * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
@@ skipping 137 matching lines @@
         self._run(['svn', 'checkout', '--quiet', svn_repo_url, svn_checkout_path])
 
         # Create and checkout a trunk dir to match the standard svn configuration to match git-svn's expectations
         self._chdir(svn_checkout_path)
         self._mkdir('trunk')
         self._svn_add('trunk')
         # We can add tags and branches as well if we ever need to test those.
         self._svn_commit('add trunk')
 
         self._rmtree(svn_checkout_path)
+        self._chdir(self.original_cwd)
 
         self._set_up_svn_test_commits(svn_repo_url + "/trunk")
         return svn_repo_path
 
     def _set_up_svn_test_commits(self, svn_repo_url):
         svn_checkout_path = self._mkdtemp(suffix="svn_test_checkout")
         self._run(['svn', 'checkout', '--quiet', svn_repo_url, svn_checkout_path])
 
         # Add some test commits
         self._chdir(svn_checkout_path)
@@ skipping 22 matching lines @@
         # This 4th commit is used to make sure that our patch file handling
         # code correctly treats patches as binary and does not attempt to
         # decode them assuming they're utf-8.
         self._write_binary_file("test_file", u"latin1 test: \u00A0\n".encode("latin-1"))
         self._write_binary_file("test_file2", u"utf-8 test: \u00A0\n".encode("utf-8"))
         self._svn_commit("fourth commit")
 
         # svn does not seem to update after commit as I would expect.
         self._run(['svn', 'update'])
         self._rmtree(svn_checkout_path)
+        self._chdir(self.original_cwd)
 
     def _tear_down_svn_checkout(self):
         self._rmtree(self.temp_directory)
 
     def _shared_test_add_recursively(self):
         self._mkdir("added_dir")
         self._write_text_file("added_dir/added_file", "new stuff")
         self.scm.add("added_dir/added_file")
         self.assertIn("added_dir/added_file", self.scm._added_files())
 
@@ skipping 484 matching lines @@
         scm = self.make_scm()
         scm.find_checkout_root = lambda path: ''
         scm._run_git = lambda args: 'Date: 2013-02-08 08:05:49 +0000'
         self.assertEqual(scm.timestamp_of_revision('some-path', '12345'), '2013-02-08T08:05:49Z')
 
         scm._run_git = lambda args: 'Date: 2013-02-08 01:02:03 +0130'
         self.assertEqual(scm.timestamp_of_revision('some-path', '12345'), '2013-02-07T23:32:03Z')
 
         scm._run_git = lambda args: 'Date: 2013-02-08 01:55:21 -0800'
         self.assertEqual(scm.timestamp_of_revision('some-path', '12345'), '2013-02-08T09:55:21Z')