chromium/third_party/blink/web_tests/external/wpt/xhr/setrequestheader-before-open.htm

<!doctype html>
<html>
  <head>
    <title>XMLHttpRequest: setRequestHeader() before open()</title>
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <link rel="help" href="https://xhr.spec.whatwg.org/#the-setrequestheader()-method" data-tested-assertations="following::ol/li[1]" />
  </head>
  <body>
    <div id="log"></div>
    <script>
      test(function() {
        var client = new XMLHttpRequest()
        assert_throws_dom("InvalidStateError", function() { client.setRequestHeader("x-test", "test") })
        }, 'setRequestHeader invoked before open()')
    </script>
  </body>
</html>