diff --git a/Tests/test_image_thumbnail.py b/Tests/test_image_thumbnail.py
index 1606d8939..bdbf09c40 100644
--- a/Tests/test_image_thumbnail.py
+++ b/Tests/test_image_thumbnail.py
@@ -16,7 +16,7 @@ from .helper import (
 
 def test_sanity() -> None:
     im = hopper()
-    assert im.thumbnail((100, 100)) is None  # type: ignore[func-returns-value]
+    im.thumbnail((100, 100))
 
     assert im.size == (100, 100)