Update DOM and DOW parsing logic

- Added a special case handling when both 'day' fields are set to allow either one to match. This addresses issue #29.
- Updated the parsing logic for 'dom' and 'dow' arguments, using `_parse_arg` function with appropriate default values.

pycron/__init__.py

@@ -117,15 +117,25 @@ def is_now(s, dt=None):
     """
     if dt is None:
         dt = datetime.now()
-    minute, hour, dom, month, dow = s.split(" ")
+    minute, hour, dom, month, dow = [x.strip() for x in s.split(" ")]
     weekday = dt.isoweekday()
 
+    # Special case if both of the 'day' -fields are set -> allow either one to match
+    # See: https://github.com/kipe/pycron/issues/29
+    if "*" not in dom and "*" not in dow:
+        day_rule = _parse_arg(dom, dt.day) or _parse_arg(
+            dow, 0 if weekday == 7 else weekday, True
+        )
+    else:
+        day_rule = _parse_arg(dom, dt.day) and _parse_arg(
+            dow, 0 if weekday == 7 else weekday, True
+        )
+
     return (
         _parse_arg(minute, dt.minute)
         and _parse_arg(hour, dt.hour)
-        and _parse_arg(dom, dt.day)
         and _parse_arg(month, dt.month)
-        and _parse_arg(dow, 0 if weekday == 7 else weekday, True)
+        and day_rule
     )
 
 

tests/test_dom_dow.py

@@ -0,0 +1,30 @@
+import unittest
+from datetime import datetime
+import pycron
+from pytz import utc
+import pendulum
+import arrow
+import udatetime
+from delorean import Delorean
+
+
+class DOMDOWTestCase(unittest.TestCase):
+    def test_dom(self):
+        def run(now):
+            assert pycron.is_now("* * * * *", now)
+            assert pycron.is_now("* * 22 * thu", now)
+            assert pycron.is_now("* * 23 * thu", now)
+            assert pycron.is_now("* * 23 * fri", now)
+            assert pycron.is_now("* * 23 * *", now)
+            assert pycron.is_now("* * * * thu", now)
+            assert pycron.is_now("* * * * *", now)
+            assert pycron.is_now("* * * * fri", now) is False
+            assert pycron.is_now("* * 22 * *", now) is False
+
+        now = datetime(2022, 6, 23, 16, 44)  # Thursday
+        run(now)
+        run(now.replace(tzinfo=utc))
+        run(pendulum.instance(now))
+        run(arrow.get(now))
+        run(udatetime.from_string(now.isoformat()))
+        run(Delorean(datetime=now, timezone="UTC").datetime)