--- a/testing/mochitest/browser-test.js
+++ b/testing/mochitest/browser-test.js
@@ -456,17 +456,17 @@ Tester.prototype = {
           // stringified gives the original string.  As in, this is in fact a
           // string representation of an integer, so an index into
           // window.frames.  Skip those.
           return;
         }
         if (this._globalProperties.indexOf(prop) == -1) {
           this._globalProperties.push(prop);
           if (this._globalPropertyWhitelist.indexOf(prop) == -1)
-            this.currentTest.addResult(new testResult(false, "leaked window property: " + prop, "", false));
+            this.currentTest.addResult(new testResult(false, "test left unexpected property on window: " + prop, "", false));
         }
       }, this);
 
       // Clear document.popupNode.  The test could have set it to a custom value
       // for its own purposes, nulling it out it will go back to the default
       // behavior of returning the last opened popup.
       document.popupNode = null;