gecko-dev/browser/base/content/test/general/browser_bug491431.js

/* 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/. */

var testPage = "data:text/plain,test bug 491431 Page";

function test() {
  waitForExplicitFinish();

  let newWin, tabA, tabB;

  // test normal close
  tabA = BrowserTestUtils.addTab(gBrowser, testPage);
  gBrowser.tabContainer.addEventListener(
    "TabClose",
    function (firstTabCloseEvent) {
      ok(!firstTabCloseEvent.detail.adoptedBy, "This was a normal tab close");

      // test tab close by moving
      tabB = BrowserTestUtils.addTab(gBrowser, testPage);
      gBrowser.tabContainer.addEventListener(
        "TabClose",
        function (secondTabCloseEvent) {
          executeSoon(function () {
            ok(
              secondTabCloseEvent.detail.adoptedBy,
              "This was a tab closed by moving"
            );

            // cleanup
            newWin.close();
            executeSoon(finish);
          });
        },
        { capture: true, once: true }
      );
      newWin = gBrowser.replaceTabWithWindow(tabB);
    },
    { capture: true, once: true }
  );
  gBrowser.removeTab(tabA);
}