fix: handle tz-aware datetimes in naturalday and naturaldate (#297)

Author: bysiber

src/humanize/time.py

@@ -319,14 +319,20 @@ def naturalday(value: dt.date | dt.datetime, format: str = "%b %d") -> str:
     import datetime as dt
 
     try:
+        # When value is a tz-aware datetime, compute "today" in that timezone
+        # so the comparison uses the correct local date.
+        if isinstance(value, dt.datetime) and value.tzinfo is not None:
+            today = dt.datetime.now(value.tzinfo).date()
+        else:
+            today = dt.date.today()
         value = dt.date(value.year, value.month, value.day)
     except AttributeError:
         # Passed value wasn't date-ish
         return str(value)
     except (OverflowError, ValueError):
         # Date arguments out of range
         return str(value)
-    delta = value - dt.date.today()
+    delta = value - today
 
     if delta.days == 0:
         return _("today")
@@ -344,18 +350,23 @@ def naturaldate(value: dt.date | dt.datetime) -> str:
     """Like `naturalday`, but append a year for dates more than ~five months away."""
     import datetime as dt
 
+    original_value = value
     try:
+        if isinstance(value, dt.datetime) and value.tzinfo is not None:
+            today = dt.datetime.now(value.tzinfo).date()
+        else:
+            today = dt.date.today()
         value = dt.date(value.year, value.month, value.day)
     except AttributeError:
         # Passed value wasn't date-ish
         return str(value)
     except (OverflowError, ValueError):
         # Date arguments out of range
         return str(value)
-    delta = _abs_timedelta(value - dt.date.today())
+    delta = _abs_timedelta(value - today)
     if delta.days >= 5 * 365 / 12:
-        return naturalday(value, "%b %d %Y")
-    return naturalday(value)
+        return naturalday(original_value, "%b %d %Y")
+    return naturalday(original_value)
 
 
 def _quotient_and_remainder(

tests/test_time.py

@@ -300,6 +300,32 @@ def test_naturaldate(test_input: dt.date, expected: str) -> None:
     assert humanize.naturaldate(test_input) == expected
 
 
+@freeze_time("2023-10-15 23:00:00+00:00")
+def test_naturaldate_tz_aware() -> None:
+    """naturaldate should compare dates in the timezone of the given value."""
+    utc = dt.timezone.utc
+    aedt = dt.timezone(dt.timedelta(hours=11))
+    cest = dt.timezone(dt.timedelta(hours=2))
+    edt = dt.timezone(dt.timedelta(hours=-4))
+    pdt = dt.timezone(dt.timedelta(hours=-7))
+    future = dt.datetime(2023, 10, 16, hour=6, tzinfo=utc)
+
+    # UTC: now is Oct 15, future is Oct 16 => tomorrow
+    assert humanize.naturaldate(future) == "tomorrow"
+
+    # AEDT (+11): now is Oct 16 10:00, future is Oct 16 17:00 => today
+    assert humanize.naturaldate(future.astimezone(aedt)) == "today"
+
+    # CEST (+2): now is Oct 16 01:00, future is Oct 16 08:00 => today
+    assert humanize.naturaldate(future.astimezone(cest)) == "today"
+
+    # EDT (-4): now is Oct 15 19:00, future is Oct 16 02:00 => tomorrow
+    assert humanize.naturaldate(future.astimezone(edt)) == "tomorrow"
+
+    # PDT (-7): now is Oct 15 16:00, future is Oct 15 23:00 => today
+    assert humanize.naturaldate(future.astimezone(pdt)) == "today"
+
+
 @pytest.mark.parametrize(
     "seconds, expected",
     [