diff --git a/tests/serializers/test_union.py b/tests/serializers/test_union.py
index cbdfd09ef..0f5c23efd 100644
--- a/tests/serializers/test_union.py
+++ b/tests/serializers/test_union.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import dataclasses
 import json
 import uuid