diff --git a/test/mask.c b/test/mask.c
index 6d0e45878..2f0349d84 100644
--- a/test/mask.c
+++ b/test/mask.c
@@ -81,8 +81,7 @@ mask_polygon (cairo_t *cr, int x, int y)
     cr2 = cairo_create (mask_surface);
 
     cairo_save (cr2);
-    cairo_set_source_rgba (cr2, 0, 0, 0, 0); /* transparent */
-    cairo_set_operator (cr2, CAIRO_OPERATOR_SOURCE);
+    cairo_set_operator (cr2, CAIRO_OPERATOR_CLEAR);
     cairo_paint (cr2);
     cairo_restore (cr2);