diff --git a/tests/content/test_interfaces.html b/tests/content/test_interfaces.html
index 2989fb83957..f44b0110e66 100644
--- a/tests/content/test_interfaces.html
+++ b/tests/content/test_interfaces.html
@@ -55,6 +55,8 @@ var interfaceNamesInGlobalScope = [
   "Blob",
   "CanvasRenderingContext2D",
   "CharacterData",
+  "CSS2Properties",
+  "CSSStyleDeclaration",
   "DOMRect",
   "Comment",
   "Console",
@@ -69,7 +71,7 @@ var interfaceNamesInGlobalScope = [
   "DOMTokenList",
   "DOMStringMap",
   "Element",
-  "ErrorEvent"
+  "ErrorEvent",
   "Event",
   "EventTarget",
   "File",