more validation test

tests/validation/config.json

@@ -15,7 +15,12 @@
             "title": "Node material #3",
             "playgroundId": "#LWGVT0#2",
             "referenceImage": "node-material3.png"
-        },          
+        },     
+        {
+            "title": "Node material #4",
+            "playgroundId": "#ZYGRII#0",
+            "referenceImage": "node-material4.png"
+        },       
         {
             "title": "Basis loader",
             "playgroundId": "#4RN0VF#0",