diff -r 000000000000 -r 6474c204b198 toolkit/components/contentprefs/tests/unit_cps2/test_extractDomain.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/components/contentprefs/tests/unit_cps2/test_extractDomain.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,20 @@
+/* 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 tests = {
+    "http://example.com": "example.com",
+    "http://example.com/": "example.com",
+    "http://example.com/foo/bar/baz": "example.com",
+    "http://subdomain.example.com/foo/bar/baz": "subdomain.example.com",
+    "http://qix.quux.example.com/foo/bar/baz": "qix.quux.example.com",
+    "file:///home/foo/bar": "file:///home/foo/bar",
+    "not a url": "not a url",
+  };
+  let cps = Cc["@mozilla.org/content-pref/service;1"].
+            getService(Ci.nsIContentPrefService2);
+  for (let url in tests) {
+    do_check_eq(cps.extractDomain(url), tests[url]);
+  }
+}