Fixed CronTrigger with jitter producing fire times beyond end_date

Fixes #269.

apscheduler/triggers/cron/__init__.py

@@ -192,9 +192,8 @@ def get_next_fire_time(self, previous_fire_time, now):
                 return None
 
         if fieldnum >= 0:
-            if self.jitter is not None:
-                next_date = self._apply_jitter(next_date, self.jitter, now)
-            return next_date
+            next_date = self._apply_jitter(next_date, self.jitter, now)
+            return min(next_date, self.end_date) if self.end_date else next_date
 
     def __getstate__(self):
         return {

docs/versionhistory.rst

@@ -9,6 +9,9 @@ APScheduler, see the :doc:`migration section <migration>`.
 
 * Fixed ``OverflowError`` on Windows when the wait time is too long
 
+* Fixed ``CronTrigger`` sometimes producing fire times beyond ``end_date`` when jitter is enabled
+  (thanks to gilbsgilbs for the tests)
+
 
 3.5.0
 -----

tests/test_triggers.py

@@ -373,6 +373,15 @@ def test_jitter_dst_change(self, trigger_args, start_date, start_date_dst, corre
             next_fire_time = trigger.get_next_fire_time(None, start_date)
             assert abs(next_fire_time - correct_next_date) <= timedelta(seconds=5)
 
+    def test_jitter_with_end_date(self, timezone):
+        now = timezone.localize(datetime(2017, 11, 12, 6, 55, 30))
+        end_date = timezone.localize(datetime(2017, 11, 12, 6, 56, 0))
+        trigger = CronTrigger(minute='*', jitter=5, end_date=end_date)
+
+        for _ in range(0, 100):
+            next_fire_time = trigger.get_next_fire_time(None, now)
+            assert next_fire_time is None or next_fire_time <= end_date
+
     @pytest.mark.parametrize('values, expected', [
         (dict(day='*/31'), "Error validating expression '\*/31': the step value \(31\) is higher "
                            "than the total range of the expression \(30\)"),
@@ -575,6 +584,15 @@ def test_jitter_dst_change(self, trigger_args, start_date, start_date_dst, corre
             next_fire_time = trigger.get_next_fire_time(None, start_date + epsilon)
             assert abs(next_fire_time - correct_next_date) <= timedelta(seconds=5)
 
+    def test_jitter_with_end_date(self, timezone):
+        now = timezone.localize(datetime(2017, 11, 12, 6, 55, 58))
+        end_date = timezone.localize(datetime(2017, 11, 12, 6, 56, 0))
+        trigger = IntervalTrigger(seconds=5, jitter=5, end_date=end_date)
+
+        for _ in range(0, 100):
+            next_fire_time = trigger.get_next_fire_time(None, now)
+            assert next_fire_time is None or next_fire_time <= end_date
+
 
 class TestAndTrigger(object):
     @pytest.fixture