add tests to canceled enrollment or scheduled with seat

enrollments-events/tests/events/test_restore_seat_on_canceled.py

@@ -0,0 +1,20 @@
+from aws_lambda_powertools.utilities.typing import LambdaContext
+from layercake.dynamodb import DynamoDBPersistenceLayer
+
+import events.restore_seat_on_canceled as app
+
+
+def test_restore_seat_on_canceled(
+    dynamodb_seeds,
+    dynamodb_persistence_layer: DynamoDBPersistenceLayer,
+    lambda_context: LambdaContext,
+):
+    event = {
+        'detail': {
+            'old_image': {
+                'id': '',
+                'seat': {'order_id': ''},
+            },
+        }
+    }
+    assert app.lambda_handler(event, lambda_context)  # type: ignore