Add some more test cases for login

client/site_tests/login_BadAuthentication/login_BadAuthentication.py

 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from autotest_lib.client.bin import chromeos_constants, site_login, site_ui_test
 from autotest_lib.client.common_lib import error, site_auth_server
 
 class login_BadAuthentication(site_ui_test.UITest):
     version = 1
 
     auto_login = False
 
+    _errorString = None
+
     def __login_denier(self, handler, url_args):
         handler.send_response(403)
         handler.end_headers()
-        handler.wfile.write('Error=BadAuthentication.')
+        handler.wfile.write(self._errorString)
 
 
     def start_authserver(self):
         self._authServer = site_auth_server.GoogleAuthServer(
             cl_responder=self.__login_denier)
         self._authServer.run()
 
         self.use_local_dns()
 
 
-    def run_once(self):
+    def run_once(self, error_string='BadAuthentication'):
+        self._errorString = "Error=" + error_string
         # TODO(cmasone): find better way to determine login has failed.
         try:
             self.login(self.username, self.password)
         except site_login.TimeoutError:
             pass
         else:
             raise error.TestFail('Should not have logged in')
 
         self._authServer.wait_for_client_login()