diff --git a/glue/viewers/image/tests/test_viewer.py b/glue/viewers/image/tests/test_viewer.py
index fc2aea81d..1fbf875f3 100644
--- a/glue/viewers/image/tests/test_viewer.py
+++ b/glue/viewers/image/tests/test_viewer.py
@@ -9,6 +9,7 @@
 
 from shapely.geometry import Polygon, MultiPolygon
 
+
 @visual_test
 def test_simple_viewer():