diff --git a/swh/model/tests/test_model.py b/swh/model/tests/test_model.py
index 8bffa80..3f4de69 100644
--- a/swh/model/tests/test_model.py
+++ b/swh/model/tests/test_model.py
@@ -298,6 +298,7 @@ def test_release_model_id_computation():
 
     rel_id = hash_to_bytes(release_identifier(rel_dict))
     for rel_model in [Release(**rel_dict), Release.from_dict(rel_dict)]:
+        assert isinstance(rel_model.date, TimestampWithTimezone)
         assert rel_model.id == hash_to_bytes(rel_id)