diff --git a/Tests/test_imageshow.py b/Tests/test_imageshow.py
index 899c057d6f7..a2b02810ec7 100644
--- a/Tests/test_imageshow.py
+++ b/Tests/test_imageshow.py
@@ -18,18 +18,19 @@ def test_register(self):
         ImageShow._viewers.pop()
 
     def test_show(self):
-        class TestViewer:
+        class TestViewer(ImageShow.Viewer):
             methodCalled = False
 
-            def show(self, image, title=None, **options):
+            def show_image(self, image, **options):
                 self.methodCalled = True
                 return True
         viewer = TestViewer()
         ImageShow.register(viewer, -1)
 
-        im = hopper()
-        self.assertTrue(ImageShow.show(im))
-        self.assertTrue(viewer.methodCalled)
+        for mode in ("1", "I;16", "LA", "RGB", "RGBA"):
+            im = hopper(mode)
+            self.assertTrue(ImageShow.show(im))
+            self.assertTrue(viewer.methodCalled)
 
         # Restore original state
         ImageShow._viewers.pop(0)