diff --git a/Tests/test_image.py b/Tests/test_image.py
index afc6e8e16..c064939e8 100644
--- a/Tests/test_image.py
+++ b/Tests/test_image.py
@@ -466,6 +466,9 @@ class TestImage:
         # Assert
         assert Image._initialized == 2
 
+        for extension in Image.EXTENSION:
+            assert extension in Image._EXTENSION_PLUGIN
+
     def test_registered_extensions(self) -> None:
         # Arrange
         # Open an image to trigger plugin registration