chromium/src/third_party/blink/web_tests/fast/forms/select/select-validation-assertion.html

<select required="" form="form_0"></select>
<form id="form_0"></form>
<script>
if (window.testRunner)
    testRunner.dumpAsText();
document.body.remove();
document.open();
console.log('PASS if no assertion failure');
</script>