/* 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(function* () {
  // make sure that the next closed tab will increase getClosedTabCount
  let max_tabs_undo = gPrefService.getIntPref("browser.sessionstore.max_tabs_undo");
  gPrefService.setIntPref("browser.sessionstore.max_tabs_undo", max_tabs_undo + 1);
  registerCleanupFunction(() => gPrefService.clearUserPref("browser.sessionstore.max_tabs_undo"));

  // Empty the list of closed tabs.
  while (ss.getClosedTabCount(window)) {
    ss.forgetClosedTab(window, 0);
  }

  // restore a blank tab
  let tab = gBrowser.addTab("about:");
  yield promiseBrowserLoaded(tab.linkedBrowser);

  let count = yield promiseSHistoryCount(tab.linkedBrowser);
  ok(count >= 1, "the new tab does have at least one history entry");

  yield promiseTabState(tab, {entries: []});

  // We may have a different sessionHistory object if the tab
  // switched from non-remote to remote.
  count = yield promiseSHistoryCount(tab.linkedBrowser);
  is(count, 0, "the tab was restored without any history whatsoever");

  yield promiseRemoveTab(tab);
  is(ss.getClosedTabCount(window), 0,
     "The closed blank tab wasn't added to Recently Closed Tabs");
});

function promiseSHistoryCount(browser) {
  /* eslint-env mozilla/frame-script */
  return ContentTask.spawn(browser, null, function* () {
    return docShell.QueryInterface(Ci.nsIWebNavigation).sessionHistory.count;
  });
}
