The Tor Browser / file revision

 /* Any copyright is dedicated to the Public Domain.

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

 function test() {

   waitForExplicitFinish();

   newWindowWithTabView(win => {

     is(win.gBrowser.tabs.length, 1, "There is only one tab");

     let tab = win.gBrowser.tabs[0];

     let tabItem = tab._tabViewTabItem;

     ok(tabItem.parent, "The tab item belongs to a group");

     let groupId = tabItem.parent.id;

     tab._tabViewTabItem.close();

     whenTabViewIsHidden(function() {

       // a new tab with group should be opened

       is(win.gBrowser.tabs.length, 1, "There is still one tab");

       isnot(win.gBrowser.selectedTab, tab, "The tab is different");

       tab = win.gBrowser.tabs[0];

       tabItem = tab._tabViewTabItem;

       ok(tabItem.parent, "This new tab item belongs to a group");

       is(tabItem.parent.id, groupId, "The group is different");

       promiseWindowClosed(win).then(finish);

     }, win);

   });

 }