diff --git a/test/integration/cpu-render.html b/test/integration/cpu-render.html
index d6d363084..34057aee8 100644
--- a/test/integration/cpu-render.html
+++ b/test/integration/cpu-render.html
@@ -1,3 +1,9 @@
+<head>
+    <style>
+        canvas {border:1px solid black}
+    </style>
+</head>
+
 <body>
     <script src="../../node_modules/scratch-vm/dist/web/scratch-vm.js"></script>
     <script src="../../node_modules/scratch-storage/dist/web/scratch-storage.js"></script>
