Assert getcolors() does not return None

Author: radarhere

Tests/test_file_avif.py

@@ -254,7 +254,9 @@ def test_load_transparent_rgb(self) -> None:
             assert_image(im, "RGBA", (64, 64))
 
             # image has 876 transparent pixels
-            assert im.getchannel("A").getcolors()[0] == (876, 0)
+            colors = im.getchannel("A").getcolors()
+            assert colors is not None
+            assert colors[0] == (876, 0)
 
     def test_save_transparent(self, tmp_path: Path) -> None:
         im = Image.new("RGBA", (10, 10), (0, 0, 0, 0))