 promise(test)
    .then(() => {test.done();})
    .catch(test.step_func(error => { throw error; }));
  }, description);
};

promise_test_parallel(async test => {
  const iframe = document.createElement("iframe");
  iframe.csp = sandbox_policy;

  // The <iframe> immediately hosts the initial empty document after being
  // appended into the DOM. It will, as long as its 'src' isn't loaded. That's
  // why a page do not load is being used.
  iframe.src = "/fetch/api/resources/infinite-slow-response.py";
  do