diff -r 000000000000 -r 6474c204b198 toolkit/components/contentprefs/tests/unit_cps2/test_service.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/components/contentprefs/tests/unit_cps2/test_service.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,12 @@
+/* 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/. */
+
+function run_test() {
+  let serv = Cc["@mozilla.org/content-pref/service;1"].
+             getService(Ci.nsIContentPrefService2);
+  do_check_eq(serv.QueryInterface(Ci.nsIContentPrefService2), serv);
+  do_check_eq(serv.QueryInterface(Ci.nsISupports), serv);
+  let val = serv.QueryInterface(Ci.nsIContentPrefService);
+  do_check_true(val instanceof Ci.nsIContentPrefService);
+}