Removing the mutation in the factories for getting dep repositories

appengine/findit/crash/test/findit_test.py

 # Copyright 2016 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 copy
 import logging
 
 from google.appengine.api import app_identity
 
 from crash.findit import Findit
 from crash.type_enums import CrashClient
 from crash.test.crash_pipeline_test import DummyCrashData
 from crash.test.predator_testcase import PredatorTestCase
 from model.crash.fracas_crash_analysis import FracasCrashAnalysis
 
-MOCK_REPOSITORY = None
+
+MOCK_GET_REPOSITORY = lambda _: None # pragma: no cover
+
 
 class UnsupportedClient(Findit): # pylint: disable=W0223
   # TODO(http://crbug.com/659346): this isn't being called for some reason.
   @property
   def client_id(self): # pragma: no cover
     return self._client_id
 
   @property
   def config(self): # pragma: no cover
     """Don't return None, so that PlatformRename doesn't crash."""
     return {}
 
   def __init__(self, client_id=None):
-    super(UnsupportedClient, self).__init__(MOCK_REPOSITORY)
+    super(UnsupportedClient, self).__init__(MOCK_GET_REPOSITORY)
     if client_id is None:
       client_id = 'unsupported_client'
     self._client_id = client_id
 
 
 class MockFindit(Findit):  # pylint: disable = W
   """Overwrite abstract method of Findit for testing."""
 
   def __init__(self):
-    super(MockFindit, self).__init__(MOCK_REPOSITORY)
+    super(MockFindit, self).__init__(MOCK_GET_REPOSITORY)
 
   @classmethod
   def _ClientID(cls):
     return CrashClient.FRACAS
 
   def ProcessResultForPublishing(self, result, key):
     return result
 
 
 class FinditTest(PredatorTestCase):
@@ skipping 69 matching lines @@
         'client_id': self.findit.client_id,
         'result': copy.deepcopy(analysis_result),
     }
 
     analysis = FracasCrashAnalysis.Create(crash_identifiers)
     analysis.result = analysis_result
 
     self.assertDictEqual(self.findit.GetPublishableResult(crash_identifiers,
                                                           analysis),
                          expected_processed_result)