diff --git a/icekit_events/models.py b/icekit_events/models.py
index a96ad21..17ac417 100644
--- a/icekit_events/models.py
+++ b/icekit_events/models.py
@@ -46,8 +46,6 @@ def zero_datetime(dt, tz=None):
     Return the given datetime with hour/minutes/seconds/ms zeroed and the
     timezone coerced to the given ``tz`` (or UTC if none is given).
     """
-    if dt is None:
-        return None
     if tz is None:
         tz = get_current_timezone()
     return coerce_naive(dt).replace(hour=0, minute=0, second=0, microsecond=0)
@@ -70,10 +68,6 @@ def default_date_starts():
     return djtz.date()
 
 
-def default_date_ends():
-    return default_date_starts() + appsettings.DEFAULT_DATE_ENDS_DELTA
-
-
 def format_naive_ical_dt(date_or_datetime):
     """
     Return datetime formatted for use in iCal as a *naive* datetime value to
@@ -755,7 +749,7 @@ class Meta:
 
     def time_range_string(self):
         if self.is_all_day:
-            if self.duration <= timedelta(days=1):
+            if self.duration < timedelta(days=1):
                 return u"""{0}, all day""".format(
                     datefilter(self.local_start, DATE_FORMAT))
             else:
diff --git a/icekit_events/tests/tests.py b/icekit_events/tests/tests.py
index 9365d14..a17bf2d 100644
--- a/icekit_events/tests/tests.py
+++ b/icekit_events/tests/tests.py
@@ -987,6 +987,38 @@ def setUp(self):
             rounding=timeutils.ROUND_DOWN)
         self.end = self.start + appsettings.DEFAULT_ENDS_DELTA
 
+    def test_time_range_string(self):
+        event = G(SimpleEvent)
+
+        timed_occurrence = models.Occurrence.objects.create(
+            event=event,
+            start=djtz.datetime(2016,10,1, 9,0),
+            end=djtz.datetime(2016,10,1, 19,0),
+        )
+        self.assertEquals(
+            'Oct. 1, 2016 9 a.m. - Oct. 1, 2016 7 p.m.',
+            timed_occurrence.time_range_string())
+
+        single_day_all_day_occurrence = models.Occurrence.objects.create(
+            event=event,
+            start=djtz.datetime(2016,10,1, 0,0),
+            end=djtz.datetime(2016,10,1, 0,0),
+            is_all_day=True,
+        )
+        self.assertEquals(
+            'Oct. 1, 2016, all day',
+            single_day_all_day_occurrence.time_range_string())
+
+        multi_day_all_day_occurrence = models.Occurrence.objects.create(
+            event=event,
+            start=djtz.datetime(2016,10,1, 0,0),
+            end=djtz.datetime(2016,10,2, 0,0),
+            is_all_day=True,
+        )
+        self.assertEquals(
+            'Oct. 1, 2016 - Oct. 2, 2016, all day',
+            multi_day_all_day_occurrence.time_range_string())
+
     def test_initial_event_occurrences_automatically_created(self):
         event = G(SimpleEvent)
         self.assertEqual(event.occurrences.count(), 0)