diff --git a/tests/test_injection.py b/tests/test_injection.py
index 74d031a..7a55be7 100644
--- a/tests/test_injection.py
+++ b/tests/test_injection.py
@@ -277,7 +277,7 @@ def test_inject_into_required_optional() -> None:
     class Thing:
         ...
 
-    def f(i: Thing | None) -> Thing | None:
+    def f(i: Optional[Thing]) -> Optional[Thing]:
         return i
 
     with pytest.raises(TypeError, match="missing 1 required positional argument"):