The Tor Browser / file revision

 /* Any copyright is dedicated to the Public Domain.

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

 function test() {

   waitForExplicitFinish();

   window.addEventListener("tabviewshown", onTabViewWindowLoaded, false);

   TabView.toggle();

 }

 function onTabViewWindowLoaded() {

   window.removeEventListener("tabviewshown", onTabViewWindowLoaded, false);

   ok(TabView.isVisible(), "Tab View is visible");

   let onTabViewHidden = function() {

     window.removeEventListener("tabviewhidden", onTabViewHidden, false);

     ok(!TabView.isVisible(), "Tab View is hidden");

     finish();

   };

   window.addEventListener("tabviewhidden", onTabViewHidden, false);

   document.getElementById("cmd_closeWindow").doCommand();

 }