replacing the NullCulprit class by None

appengine/findit/crash/test/crash_pipeline_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 json
 import logging
 
 from google.appengine.api import app_identity
 from google.appengine.ext import ndb
 from webtest.app import AppError
@@ skipping 60 matching lines @@
     analysis.status = analysis_status.RUNNING
     analysis.put()
 
     pipeline = crash_pipeline.CrashAnalysisPipeline(
         CrashClient.FRACAS,
         crash_identifiers)
     pipeline._PutAbortedError()
     analysis = FracasCrashAnalysis.Get(crash_identifiers)
     self.assertEqual(analysis_status.ERROR, analysis.status)
 
+  def testFindCulpritFails(self):
+    crash_identifiers = DummyCrashData()['crash_identifiers']
+    analysis = FracasCrashAnalysis.Create(crash_identifiers)
+    analysis.status = analysis_status.RUNNING
+    analysis.put()
+
+    self.mock(FinditForFracas, 'FindCulprit', lambda *_: None)
+    pipeline = crash_pipeline.CrashAnalysisPipeline(
+        CrashClient.FRACAS,
+        crash_identifiers)
+    pipeline.run()
+
+    analysis = FracasCrashAnalysis.Get(crash_identifiers)
+    self.assertEqual(analysis_status.COMPLETED, analysis.status)
+    self.assertFalse(analysis.result['found'])
+    self.assertFalse(analysis.found_suspects)
+    self.assertFalse(analysis.found_project)
+    self.assertFalse(analysis.found_components)
 
   # TODO: this function is a gross hack. We should figure out what the
   # semantic goal really is here, so we can avoid doing such intricate
   # and fragile mocking.
   def _TestRunningAnalysisForResult(self, analysis_result, analysis_tags):
 
     # Mock out the part of PublishResultPipeline that would go over the wire.
     pubsub_publish_requests = []
     def Mocked_PublishMessagesToTopic(messages_data, topic):
       pubsub_publish_requests.append((messages_data, topic))
@@ skipping 152 matching lines @@
         'has_regression_range': True,
         'solution': 'core',
         'unsupported_tag': '',
     }
 
     analysis = self._TestRunningAnalysisForResult(
         analysis_result, analysis_tags)
     self.assertTrue(analysis.has_regression_range)
     self.assertTrue(analysis.found_suspects)
     self.assertEqual('core', analysis.solution)