fune/browser/components/customizableui/test/browser_947914_button_newWindow.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/. */

"use strict";

add_task(async function() {
  info("Check new window button existence and functionality");
  CustomizableUI.addWidgetToArea("new-window-button", CustomizableUI.AREA_FIXED_OVERFLOW_PANEL);
  registerCleanupFunction(() => CustomizableUI.reset());

  await waitForOverflowButtonShown();

  await document.getElementById("nav-bar").overflowable.show();
  info("Menu panel was opened");

  let windowWasHandled = false;
  let newWindow = null;

  let observerWindowOpened = {
    observe(aSubject, aTopic, aData) {
      if (aTopic == "domwindowopened") {
        newWindow = aSubject.QueryInterface(Ci.nsIDOMWindow);
        newWindow.addEventListener("load", function() {
          is(newWindow.location.href, AppConstants.BROWSER_CHROME_URL,
             "A new browser window was opened");
          ok(!PrivateBrowsingUtils.isWindowPrivate(newWindow), "Window is not private");
          windowWasHandled = true;
        }, {once: true});
      }
    }
  };

  Services.ww.registerNotification(observerWindowOpened);

  let newWindowButton = document.getElementById("new-window-button");
  ok(newWindowButton, "New Window button exists in Panel Menu");
  newWindowButton.click();

  try {
    await waitForCondition(() => windowWasHandled);
    await promiseWindowClosed(newWindow);
    info("The new window was closed");
  } catch (e) {
    ok(false, "The new browser window was not properly handled");
  } finally {
    Services.ww.unregisterNotification(observerWindowOpened);
  }
});