[Findit] Update try-job result in a transaction and fix bugs in unittests.

appengine/findit/waterfall/test/swarming_tasks_to_try_job_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 json
 
 from common.git_repository import GitRepository
 from common.pipeline_wrapper import pipeline_handlers
 from common.waterfall import buildbucket_client
 from model import result_status
@@ skipping 195 matching lines @@
     analysis = WfAnalysis.Create(master_name, builder_name, build_number)
     analysis.put()
 
     root_pipeline = SwarmingTasksToTryJobPipeline(
         master_name, builder_name, build_number, 'rev1', 'rev2', ['rev2'],
         TryJobType.COMPILE)
     root_pipeline.start()
     self.execute_queued_tasks()
 
     try_job = WfTryJob.Get(master_name, builder_name, build_number)
+    analysis = WfAnalysis.Get(master_name, builder_name, build_number)
 
     expected_suspected_cl = {
         'revision': 'rev2',
         'commit_position': '2',
         'url': 'url_2',
         'repo_name': 'chromium'
     }
 
     expected_try_job_results = [
         {
@@ skipping 115 matching lines @@
     analysis = WfAnalysis.Create(master_name, builder_name, build_number)
     analysis.put()
 
     root_pipeline = SwarmingTasksToTryJobPipeline(
         master_name, builder_name, build_number, 'rev0', 'rev1', ['rev1'],
         TryJobType.TEST, None, targeted_tests)
     root_pipeline.start()
     self.execute_queued_tasks()
 
     try_job = WfTryJob.Get(master_name, builder_name, build_number)
+    analysis = WfAnalysis.Get(master_name, builder_name, build_number)
 
     expected_suspected_cl = {
         'revision': 'rev1',
         'commit_position': '1',
         'url': 'url_1',
         'repo_name': 'chromium'
     }
 
     expected_try_job_results = [
         {
@@ skipping 25 matching lines @@
                     }
                 }
             }
         }
     ]
 
     self.assertEqual(expected_try_job_results, try_job.test_results)
     self.assertEqual(analysis.result_status,
                      result_status.FOUND_UNTRIAGED)
     self.assertEqual(analysis.suspected_cls, [expected_suspected_cl])