async_test(t => {
  const iframe = document.body.appendChild(document.createElement("iframe"));
  t.add_cleanup(() => { iframe.remove(); });
  self.testSynchronousScript = t.step_func_done(() => {
    assert_throws_dom("InvalidStateError", iframe.contentWindow.DOMException, () => {
      iframe.contentDocument.open();
    }, "opening an XML document should throw");
  });
  iframe.src = "resources/bailout-order-xml-with-synchronous-script-frame.xhtml";
}, "document.open should throw an InvalidStateError with XML document even when there is an active parser executing script");

for (const ev of ["beforeunload", "pagehide", "unload"]) {
  async_test(t => {
    const iframe = document.body.appendChild(document.createElement("iframe"));
    t.add_cleanup(() => { iframe.remove(); });
    iframe.addEventListener("load", t.step_func(() => {
      iframe.contentWindow.addEventListener(ev, t.step_func_done(() => {
        assert_throws_dom("InvalidStateError", iframe.contentWindow.DOMException, () => {
          iframe.contentDocument.open();
        }, "opening an XML document should throw");
      }));
      iframe.src = "about:blank";
    }), { once: true });
    iframe.src = "/common/dummy.xhtml";
  }, `document.open should throw an InvalidStateError with XML document even when the ignore-opens-during-unload counter is greater than 0 (during ${ev} event)`);
}