cross-origin-preflight-timeout.html

<!doctype html>
<html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<script>
async_test(t => {
    const url = 'http://localhost:8000/xmlhttprequest/resources/access-control-allow-with-delay.php';
    const xhr = new XMLHttpRequest();
    xhr.open('GET', url);
    xhr.setRequestHeader('foo', 'bar');
    xhr.timeout = 1500;
    xhr.ontimeout = t.step_func_done(() => {
      assert_equals(xhr.readyState, 4);
      });
    xhr.onload = t.unreached_func('load event fired');
    xhr.send();
  }, 'CORS preflight and the actual request should use the same timer');
</script>

chromium/third_party/blink/web_tests/http/tests/xmlhttprequest/cross-origin-preflight-timeout.html