Support cron presets in date_range function (#7777)

airflow/utils/dates.py

@@ -70,6 +70,8 @@ def date_range(start_date, end_date=None, num=None, delta=None):  # pylint: disa
         raise Exception("Wait. Either specify end_date OR num")
     if not end_date and not num:
         end_date = timezone.utcnow()
+    if delta in cron_presets:
+        delta = cron_presets.get(delta)
 
     delta_iscron = False
     time_zone = start_date.tzinfo

tests/utils/test_dates.py

@@ -94,3 +94,11 @@ class TestUtilsDatesDateRange(unittest.TestCase):
 
             for i in range(num):
                 self.assertTrue(timezone.is_localized(result[i]))
+
+    def test_delta_cron_presets(self):
+        preset_range = dates.date_range(datetime(2016, 1, 1), num=2, delta="@hourly")
+        timedelta_range = dates.date_range(datetime(2016, 1, 1), num=2, delta=timedelta(hours=1))
+        cron_range = dates.date_range(datetime(2016, 1, 1), num=2, delta="0 * * * *")
+
+        self.assertEqual(preset_range, timedelta_range)
+        self.assertEqual(preset_range, cron_range)