Saved at 2025-01-04 09:55:09 (Sat)

Author: dycw

src/tests/test_datetime.py

@@ -184,13 +184,18 @@ def test_main(self, *, date: dt.date, days: int) -> None:
         with assume_does_not_raise(OverflowError):
             timedelta = days * DAY
         with assume_does_not_raise(OverflowError):
-            result = date_add_timedelta(date, timedelta)
+            result = date_add_timedelta(date, timedelta=timedelta)
         assert is_instance_date_not_datetime(result)
 
+    @given(date=dates())
+    def test_none(self, *, date: dt.date) -> None:
+        result = date_add_timedelta(date)
+        assert result == date
+
     @given(date=dates())
     def test_error(self, *, date: dt.date) -> None:
         with raises(DateAddTimeDeltaError, match="Timedelta must be day-only; got .*"):
-            _ = date_add_timedelta(date, SECOND)
+            _ = date_add_timedelta(date, timedelta=SECOND)
 
 
 class TestDateToDatetime:

src/utilities/datetime.py

@@ -112,9 +112,13 @@ def __str__(self) -> str:
 ##
 
 
-def date_add_timedelta(date: dt.date, timedelta: dt.timedelta, /) -> dt.date:
+def date_add_timedelta(
+    date: dt.date, /, *, timedelta: dt.timedelta | None = None
+) -> dt.date:
     """Add a timedelta to a date, checking that it remains a date."""
     check_date_not_datetime(date)
+    if timedelta is None:
+        return date
     if (timedelta.seconds != 0) or (timedelta.microseconds != 0):
         raise DateAddTimeDeltaError(timedelta=timedelta)
     return date + timedelta