[Findit] Fix flaky tests due to importing pytz.

appengine/findit/waterfall/flake/recursive_flake_pipeline.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 logging
 from datetime import timedelta
 import random
 
 from common import appengine_util
 from common import constants
@@ skipping 30 matching lines @@
     manually_triggered (bool): True if the analysis is from manual request, like
         by a Chromium sheriff.
 
   Returns:
     The ETA as of a UTC datetime.datetime to start the analysis.
   """
   if manually_triggered:
     # If the analysis is manually triggered, run it right away.
     return time_util.GetUTCNow()
 
-  now_at_mtv = time_util.GetDatetimeInTimezone(
+  now_at_pst = time_util.GetDatetimeInTimezone(
       'US/Pacific', time_util.GetUTCNowWithTimezone())
-  if now_at_mtv.weekday() >= 5:  # PST Saturday or Sunday.
+  if now_at_pst.weekday() >= 5:  # PST Saturday or Sunday.
     return time_util.GetUTCNow()
 
-  if now_at_mtv.hour < 11 or now_at_mtv.hour >= 18:  # Before 11am or after 6pm.
+  if now_at_pst.hour < 11 or now_at_pst.hour >= 18:  # Before 11am or after 6pm.
     return time_util.GetUTCNow()
 
   # Set ETA time to 6pm, and also with a random latency within 30 minutes to
   # avoid sudden burst traffic to Swarming.
-  diff = timedelta(hours=18 - now_at_mtv.hour,
-                   minutes=-now_at_mtv.minute,
-                   seconds=-now_at_mtv.second + random.randint(0, 30 * 60),
-                   microseconds=-now_at_mtv.microsecond)
-  eta = now_at_mtv + diff
+  diff = timedelta(hours=18 - now_at_pst.hour,
+                   minutes=-now_at_pst.minute,
+                   seconds=-now_at_pst.second + random.randint(0, 30 * 60),
+                   microseconds=-now_at_pst.microsecond)
+  eta = now_at_pst + diff
 
   # Convert back to UTC.
   return time_util.GetDatetimeInTimezone('UTC', eta)
 
 
 class RecursiveFlakePipeline(BasePipeline):
 
   def __init__(self, *args, **kwargs):
     super(RecursiveFlakePipeline, self).__init__(*args, **kwargs)
     self.manually_triggered = kwargs.get('manually_triggered', False)
@@ skipping 195 matching lines @@
           flakiness_algorithm_results_dict=flakiness_algorithm_results_dict,
           manually_triggered=manually_triggered)
       # pylint: disable=W0201
       pipeline_job.target = appengine_util.GetTargetNameForModule(
           constants.WATERFALL_BACKEND)
       pipeline_job.StartOffPSTPeakHours(
           queue_name=self.queue_name or constants.DEFAULT_QUEUE)
     else:
       _UpdateAnalysisStatusUponCompletion(
           master_flake_analysis, analysis_status.COMPLETED, None)