[Findit] For automatic analyses of flaky tests, run the Swarming tasks off PST peak hours.

appengine/findit/common/time_util.py

Index: appengine/findit/common/time_util.py
diff --git a/appengine/findit/common/time_util.py b/appengine/findit/common/time_util.py
index 0d56e86b4eafdb9a0b457b12f7d4a11b478b77f1..407ed700f72e2dc11212c30d2be6190a907157bb 100644
--- a/appengine/findit/common/time_util.py
+++ b/appengine/findit/common/time_util.py
@@ -7,12 +7,19 @@ from datetime import datetime
 from datetime import time
 from datetime import timedelta
 
+import pytz
+
 
 def GetUTCNow():  # pragma: no cover.
   """Returns the datetime.utcnow. This is to mock for testing."""
   return datetime.utcnow()
 
 
+def GetUTCNowWithTimezone():  # pragma: no cover.
+  """Returns datetime.now but in utc timezone. This is to mock for testing."""
+  return datetime.now(pytz.utc)
+
+
 def GetUTCNowTimestamp():  # pragma: no cover.
   """Returns the timestamp for datetime.utcnow. This is to mock for testing."""
   return calendar.timegm(GetUTCNow().timetuple())
@@ -36,3 +43,18 @@ def FormatDatetime(date):
     return None
   else:
     return date.strftime('%Y-%m-%d %H:%M:%S UTC')
+
+
+def GetDatetimeInTimezone(timezone_name, date_time=None):
+  """Returns the datetime.datetime of the given one in the specified timezone.
+
+  Args:
+    timezone_name (str): The name of any timezone supported by pytz.
+    date_time (datetime.datetime): The optional datetime to be converted into
+        the new timezone. If not given, default to UTC now.

[lijeffrey, 2016/09/27 23:48:05]

Is there a reason we don't just pass the default
date_time=GetUTCNowWithTimezone()?

i.e.
def GetDatetimeInTimezone(timezone_name, date_time=GetUTCNowWithTimezone()):
  ...

[stgao, 2016/10/01 05:55:25]

No, we can't.
Default value is created and set once and then used afterwards.
For time, it depends on when the function is called.

+
+  Returns:
+    A datetime.datetime of the given one in the specified timezone.
+  """
+  date_time = date_time or GetUTCNowWithTimezone()
+  return date_time.astimezone(pytz.timezone(timezone_name))