Merge ~nobuto/juju-wait:tz into juju-wait:master

[Nobuto Murata]

[Stuart Bishop (stub)]

Code looks good. Unfortunately datetime.timezone is Python3 only. I think I'm stuck needing Python2.7 compatibility for a while longer, due to juju-wait being embedded in Mojo and IIRC some CI systems around the place.

review: Needs Fixing

[Stuart Bishop (stub)]

This is important, so lets land this now. We can address Python2 compatibility later if it still is a problem.

review: Approve

diff --git a/juju_wait/__init__.py b/juju_wait/__init__.py
index be706ca..0ea6196 100755
--- a/juju_wait/__init__.py
+++ b/juju_wait/__init__.py
@@ -19,7 +19,7 @@
 
 import argparse
 from collections import namedtuple
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 from distutils.version import LooseVersion
 import json
 import logging
@@ -60,7 +60,7 @@ class MachineState(object):
 
 def parse_ts(ts):
     """Parse the Juju provided timestamp, which must be UTC."""
-    return datetime.strptime(ts, "%d %b %Y %H:%M:%SZ")
+    return datetime.strptime(ts, "%d %b %Y %H:%M:%SZ").replace(tzinfo=timezone.utc)
 
 
 class JujuWaitException(Exception):
@@ -486,7 +486,7 @@ def wait(
 
             # Check workload status
             if current not in WORKLOAD_OK_STATES and wait_for_workload:
-                logging.debug("{} workload status is {} since " "{}Z".format(uname, current, since))
+                logging.debug("{} workload status is {} since " "{}".format(uname, current, since))
                 if uname not in exclude_units:
                     ready = False
                 else:
@@ -519,7 +519,7 @@ def wait(
                 # update-status is an idle hook event
                 pass
             elif current != "idle":
-                logging.debug("{} juju agent status is {} since " "{}Z".format(uname, current, since))
+                logging.debug("{} juju agent status is {} since " "{}".format(uname, current, since))
                 ready = False
 
         # Log storage to compare with prev_logs.