Add datetime.timezone.utc tzinfo to Timestamp.datetime

tests/test_bugs.py

@@ -5,6 +5,7 @@
     Tests for validating reported bugs have been fixed.
 """
 import copy
+import datetime
 
 import pytest
 
@@ -47,3 +48,14 @@ def test_github_issue_452():
     """
     result = copy.deepcopy(api.new())
     assert result is not None
+
+
+def test_github_issue_463():
+    """
+    Assert that :meth:`~ulid.ulid.Timestamp.datetime` returns the value as
+    a :class:`~datetime.datetime` instance that is UTC aware.
+
+    Issue: https://github.com/ahawker/ulid/issues/463
+    """
+    instance = api.new()
+    assert instance.timestamp().datetime.tzinfo == datetime.timezone.utc

tests/test_ulid.py

@@ -322,14 +322,15 @@ def test_timestamp_coverts_bytes_to_unix_time_seconds():
     assert timestamp.timestamp == now_ms / 1000.0
 
 
-def test_timestamp_converts_to_datetime():
+def test_timestamp_converts_to_utc_aware_datetime():
     """
     Assert that :meth:`~ulid.ulid.Timestamp.datetime` returns the value as
-    a :class:`~datetime.dateime` instance.
+    a :class:`~datetime.datetime` instance that is UTC aware.
     """
     now_ms = int(time.time()) * 1000
+    timezone = datetime.timezone.utc
     timestamp = ulid.Timestamp(now_ms.to_bytes(6, byteorder='big'))
-    assert timestamp.datetime == datetime.datetime.utcfromtimestamp(now_ms / 1000.0)
+    assert timestamp.datetime == datetime.datetime.utcfromtimestamp(now_ms / 1000.0).replace(tzinfo=timezone)
 
 
 def test_ulid_timestamp_returns_instance(valid_bytes_128):

ulid/ulid.py

@@ -226,8 +226,12 @@ def datetime(self) -> hints.Datetime:
         :return: Timestamp in datetime form.
         :rtype: :class:`~datetime.datetime`
         """
-        mills = self.int
-        return datetime.datetime.utcfromtimestamp(mills // 1000.0).replace(microsecond=mills % 1000 * 1000)
+        milli = self.int
+        micro = milli % 1000 * 1000
+        sec = milli // 1000.0
+        timezone = datetime.timezone.utc
+
+        return datetime.datetime.utcfromtimestamp(sec).replace(microsecond=micro, tzinfo=timezone)
 
 
 class Randomness(MemoryView):