diff -r 000000000000 -r 6474c204b198 js/xpconnect/tests/unit/test_bug451678.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/xpconnect/tests/unit/test_bug451678.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+
+function run_test() {
+  var file = do_get_file("bug451678_subscript.js");
+  var ios = Cc["@mozilla.org/network/io-service;1"]
+              .getService(Ci.nsIIOService);
+  var uri = ios.newFileURI(file);
+  var scriptLoader = Cc["@mozilla.org/moz/jssubscript-loader;1"]
+                       .getService(Ci.mozIJSSubScriptLoader);
+  var srvScope = {};
+  scriptLoader.loadSubScript(uri.spec, srvScope);
+  do_check_true('makeTags' in srvScope && srvScope.makeTags instanceof Function);
+}