Add tests for timezone-aware datetimes

template_app/tests/models/test_timezone_datetimes.py

@@ -0,0 +1,54 @@
+from datetime import datetime, timedelta, timezone
+import uuid
+
+from baselayer.app.models import DBSession, User, init_db
+from baselayer.app.env import load_config
+
+cfg = load_config(config_files=["test_config.yaml"])
+init_db(**cfg["database"])
+
+
+def test_input_timezone_is_respected():
+    # This is 2021-03-24 2PM (PDT) - Los Angeles time
+    pdt_2pm = datetime.fromisoformat("2021-03-24T14:00:00-07:00")
+
+    # Create a new User with a created_at at 2021-03-24 2PM (PDT)
+    username = uuid.uuid4().hex
+    user = User(username=username, created_at=pdt_2pm)
+    DBSession.add(user)
+    DBSession.commit()
+    assert user.created_at == pdt_2pm
+
+    # Since the User was created at 2PM (PDT), which is 7 hours behind UTC,
+    # the database should have stored 9PM that day as the created_at.
+    # So if we filter by created_at < 7PM on that day, we should not see the
+    # new user.
+    #
+    # If the created_at field were using default behavior instead
+    # of the custom TZDateTime type, the timezone info inputed above would
+    # just be ignored and 2PM put in as the time instead of being used to
+    # convert to a correct UTC timestamp before being added to the database.
+    # So, if this query returns the user, we know timezone info was ignored on
+    # SQLAlchemy datetime inputs.
+    utc_7pm = datetime.fromisoformat("2021-03-24T19:00:00")
+    users = (
+        DBSession.query(User)
+        .filter(User.username == username, User.created_at < utc_7pm)
+        .all()
+    )
+
+    assert len(users) == 0
+
+
+def test_retrieved_datetimes_have_timezone_info():
+    # Create a new User
+    username = uuid.uuid4().hex
+    user = User(username=username)
+    DBSession.add(user)
+    DBSession.commit()
+
+    # Verify that datetimes retrieved from the database are tagged with timezone info
+    user = DBSession.query(User).filter(User.username == username).first()
+    assert user is not None
+    assert user.created_at.tzinfo is not None
+    assert user.created_at.tzinfo == timezone.utc