The Tor Browser / file revision

 /* Any copyright is dedicated to the Public Domain.

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

 function test() {

   waitForExplicitFinish();

   newWindowWithTabView(function (win) {

     registerCleanupFunction(function () win.close());

     for (let i = 0; i < 4; i++)

       win.gBrowser.loadOneTab("about:blank", {inBackground: true});

     let cw = win.TabView.getContentWindow();

     let groupItem = cw.GroupItems.groupItems[0];

     let children = groupItem.getChildren();

     groupItem.setSize(200, 200, true);

     ok(groupItem.isStacked(), "groupItem is now stacked");

     is(win.gBrowser.tabs.length, 5, "we have five tabs");

     groupItem.addSubscriber("expanded", function onExpanded() {

       groupItem.removeSubscriber("expanded", onExpanded);

       ok(groupItem.expanded, "groupItem is expanded");

       let bounds = children[1].getBounds();

       // remove two tabs and see if the remaining tabs are re-arranged to fill

       // the resulting gaps

       for (let i = 0; i < 2; i++) {

         EventUtils.synthesizeMouseAtCenter(children[1].container, {button: 1}, cw);

         ok(bounds.equals(children[1].getBounds()), "tabItems were re-arranged");

       }

       waitForFocus(finish);

     });

     groupItem.expand();

   });

 }