diff -r 000000000000 -r 6474c204b198 testing/modules/AppInfo.jsm
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/testing/modules/AppInfo.jsm	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,74 @@
+/* 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/. */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = [
+  "getAppInfo",
+  "updateAppInfo",
+];
+
+
+const {interfaces: Ci, results: Cr, utils: Cu} = Components;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+
+let APP_INFO = {
+  vendor: "Mozilla",
+  name: "xpcshell",
+  ID: "xpcshell@tests.mozilla.org",
+  version: "1",
+  appBuildID: "20121107",
+  platformVersion: "p-ver",
+  platformBuildID: "20121106",
+  inSafeMode: false,
+  logConsoleErrors: true,
+  OS: "XPCShell",
+  XPCOMABI: "noarch-spidermonkey",
+  QueryInterface: XPCOMUtils.generateQI([Ci.nsIXULAppInfo, Ci.nsIXULRuntime]),
+  invalidateCachesOnRestart: function() {},
+};
+
+
+/**
+ * Obtain a reference to the current object used to define XULAppInfo.
+ */
+this.getAppInfo = function () { return APP_INFO; }
+
+/**
+ * Update the current application info.
+ *
+ * If the argument is defined, it will be the object used. Else, APP_INFO is
+ * used.
+ *
+ * To change the current XULAppInfo, simply call this function. If there was
+ * a previously registered app info object, it will be unloaded and replaced.
+ */
+this.updateAppInfo = function (obj) {
+  obj = obj || APP_INFO;
+  APP_INFO = obj;
+
+  let id = Components.ID("{fbfae60b-64a4-44ef-a911-08ceb70b9f31}");
+  let cid = "@mozilla.org/xre/app-info;1";
+  let registrar = Components.manager.QueryInterface(Ci.nsIComponentRegistrar);
+
+  // Unregister an existing factory if one exists.
+  try {
+    let existing = Components.manager.getClassObjectByContractID(cid, Ci.nsIFactory);
+    registrar.unregisterFactory(id, existing);
+  } catch (ex) {}
+
+  let factory = {
+    createInstance: function (outer, iid) {
+      if (outer != null) {
+        throw Cr.NS_ERROR_NO_AGGREGATION;
+      }
+
+      return obj.QueryInterface(iid);
+    },
+  };
+
+  registrar.registerFactory(id, "XULAppInfo", cid, factory);
+};
+