compare colors as sets rather than lists

Tests/test_image_transform.py

@@ -173,10 +173,10 @@ class TestImageTransform:
         im = op(im, (40, 10))
 
         colors = im.getcolors()
-        assert colors == [
+        assert set(colors) == {
             (20 * 10, opaque),
             (20 * 10, transparent),
-        ]
+        }
 
     @pytest.mark.parametrize("mode", ("RGBA", "LA"))
     def test_nearest_resize(self, mode):