The Tor Browser / file revision

 /* Any copyright is dedicated to the Public Domain.

    http://creativecommons.org/publicdomain/zero/1.0/ */

 function test() {

   waitForExplicitFinish();

   gBrowser.selectedTab = gBrowser.addTab();

   gBrowser.selectedBrowser.addEventListener("load", function () {

     gBrowser.selectedBrowser.removeEventListener("load", arguments.callee, true);

     content.history.pushState({}, "2", "2.html");

     testBackButton();

   }, true);

   loadURI("http://example.com");

 }

 function testBackButton() {

   var backButton = document.getElementById("back-button");

   var rect = backButton.getBoundingClientRect();

   info("waiting for the history menu to open");

   backButton.addEventListener("popupshown", function (event) {

     backButton.removeEventListener("popupshown", arguments.callee, false);

     ok(true, "history menu opened");

     event.target.hidePopup();

     gBrowser.removeTab(gBrowser.selectedTab);

     finish();

   }, false);

   EventUtils.synthesizeMouseAtCenter(backButton, {type: "mousedown"});

   EventUtils.synthesizeMouse(backButton, rect.width / 2, rect.height, {type: "mouseup"});

 }