diff --git a/types/openlayers/openlayers-tests.ts b/types/openlayers/openlayers-tests.ts
index 2d2d22d411..ce13ae8385 100644
--- a/types/openlayers/openlayers-tests.ts
+++ b/types/openlayers/openlayers-tests.ts
@@ -638,7 +638,8 @@ let tileWMS: ol.source.TileWMS = new ol.source.TileWMS({
     params: {},
     projection,
     serverType: stringValue,
-    url: stringValue
+    url: stringValue,
+    transition: 0.5
 });
 
 // test without projection