Changed FindSuspects to take a Repository factory, rather than mutating it

appengine/findit/crash/loglinear/test/changelist_classifier_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 math
 import pprint
 
 from common.dependency import DependencyRoll
 from common import chrome_dependency_fetcher
@@ skipping 99 matching lines @@
 
 class LogLinearChangelistClassifierTest(CrashTestSuite):
 
   def setUp(self):
     super(LogLinearChangelistClassifierTest, self).setUp()
     weights = {
         'MinDistance': 1.,
         'TopFrameIndex': 1.,
     }
 
+    repository = GitilesRepository(self.GetMockHttpClient())
+
+    # TODO(crbug.com/677224): should replace this with an actual factory.
+    def MutateTheRepo(dep_url): # pragma: no cover
+      """A factory function for returning ``Repository`` objects.
+
+      The current definition captures the functionality of before
+      we factored out this factory method. That is, it's not really a
+      "factory" but rather mutates the main repo object in place. In
+      the future this should be changed to do the right thing instead.
+      """
+      repository.repo_url = dep_url
+      return repository
+
     self.changelist_classifier = (
         loglinear_changelist_classifier.LogLinearChangelistClassifier(
-          GitilesRepository(self.GetMockHttpClient()), weights))
+            repository, MutateTheRepo, weights))
 
   def testAggregateChangedFilesAggreegates(self):
     """Test that ``AggregateChangedFiles`` does aggregate reasons per file.
 
     In the main/inner loop of ``AggregateChangedFiles``: if multiple
     features all blame the same file change, we try to aggregate those
     reasons so that we only report the file once (with all reasons). None
     of the other tests here actually check the case where the same file
     is blamed multiple times, so we check that here.
 
@@ skipping 257 matching lines @@
     self.mock(changelist_classifier, 'FindSuspects', _MockFindSuspects)
     self.mock(chrome_dependency_fetcher.ChromeDependencyFetcher,
         'GetDependencyRollsDict',
         lambda *_: {'src/': DependencyRoll('src/', 'https://repo', '1', '2')})
     self.mock(chrome_dependency_fetcher.ChromeDependencyFetcher,
         'GetDependency', lambda *_: {})
 
     suspects = self.changelist_classifier(DUMMY_REPORT)
     self.assertFalse(suspects, 'Expected zero suspects, but found some:\n%s'
         % pprint.pformat([suspect.ToDict() for suspect in suspects]))