chromium/third_party/blink/web_tests/external/wpt/xhr/open-parameters-toString.htm

<!doctype html>
<title>XMLHttpRequest: open() attempts to toString its string parameters</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="log"></div>
<script>
test(() => {
  let log = [];
  let expected = [
    'method',
    'url',
    // NOTE: 'async' intentionally missing
    'username',
    'password',
  ];

  let xhr = new XMLHttpRequest;
  xhr.open(
    {
      toString() {
        log.push('method');
        return 'get';
      },
    },
    {
      toString() {
        log.push('url');
        return location.href;
      },
    },
    // NOTE: ToBoolean should not invoke valueOf
    {
      valueOf() {
        log.push('async');
        return true;
      },
    },
    {
      toString() {
        log.push('username');
        return 'username';
      },
    },
    {
      toString() {
        log.push('password');
        return 'password';
      },
    }
  );

  assert_array_equals(log, expected);
});
</script>