Added date_util tests back in and handle null time obj.

cms/djangoapps/models/settings/course_details.py

@@ -73,9 +73,9 @@ class CourseDetails(object):
         """
         Decode the json into CourseDetails and save any changed attrs to the db
         """
-        # # TODO make it an error for this to be undefined & for it to not be retrievable from modulestore
+        # TODO make it an error for this to be undefined & for it to not be retrievable from modulestore
         course_location = jsondict['course_location']
-        # # Will probably want to cache the inflight courses because every blur generates an update
+        # Will probably want to cache the inflight courses because every blur generates an update
         descriptor = get_modulestore(course_location).get_item(course_location)
 
         dirty = False

common/lib/xmodule/xmodule/tests/test_date_utils.py

@@ -0,0 +1,20 @@
+# Tests for xmodule.util.date_utils
+
+from nose.tools import assert_equals
+from xmodule.util import date_utils
+import datetime
+from pytz import UTC
+
+
+def test_get_default_time_display():
+    assert_equals("", date_utils.get_default_time_display(None))
+    test_time = datetime.datetime(1992, 3, 12, 15, 3, 30, tzinfo=UTC)
+    assert_equals(
+        "Mar 12, 1992 at 15:03 UTC",
+        date_utils.get_default_time_display(test_time))
+    assert_equals(
+        "Mar 12, 1992 at 15:03 UTC",
+        date_utils.get_default_time_display(test_time, True))
+    assert_equals(
+        "Mar 12, 1992 at 15:03",
+        date_utils.get_default_time_display(test_time, False))

common/lib/xmodule/xmodule/util/date_utils.py

@@ -8,6 +8,8 @@ def get_default_time_display(dt, show_timezone=True):
     If None is passed in for dt, an empty string will be returned.
     The default value of show_timezone is True.
     """
+    if dt is None:
+        return ""
     timezone = ""
     if dt is not None and show_timezone:
         if dt.tzinfo is not None: