UXP-Fixed/testing/mochitest/tests/browser/browser_zz_fail_openwindow.js

function test() {
  waitForExplicitFinish();
  function done() {
    ok(true, "timeout ran");
    finish();
  }

  ok(OpenBrowserWindow(), "opened browser window");
  // and didn't close it!

  setTimeout(done, 10000);
}