document-domain-canonicalizes-iframe.html

<!DOCTYPE html>
<head>
  <script src="/resources/testharness.js"></script>
  <script src="/resources/testharnessreport.js"></script>
</head>
<body>
<iframe></iframe>

<script>
  let iframe = document.querySelector("iframe");
  function navigate_iframe(url) {
    return new Promise(resolve => {
      iframe.onload = resolve;
      iframe.src = url;
    });
  };

  // Navigate the iframe to URLs whose host aren't canonical. They need to be
  // percent encoded. Several navigation are made to ensure potential assertions
  // can be reached before the end of the test. See https://crbug.com/901489.
  promise_test(async function(t) {
    await navigate_iframe("http://foo,.example.test/resources/dummy.html");
    await navigate_iframe("http://bar,.example.test/resources/dummy.html");
    await navigate_iframe("http://baz,.example.test/resources/dummy.html");
  }, "Navigate iframe to URL with non-canonicalized hostname");
</script>
</body>

chromium/third_party/blink/web_tests/http/tests/security/document-domain-canonicalizes-iframe.html