chromium/src/third_party/blink/web_tests/fast/dom/HTMLDocument/clone-node.html

<!-- quirks mode -->
<title>Tests HTMLDocument cloneNode</title>
<link rel="help" href="https://dom.spec.whatwg.org/#dom-node-clonenode">
<script src="../../../resources/js-test.js"></script>
<script>
description('Tests cloneNode for HTMLDocument.');

function className(object) {
    return Object.prototype.toString.call(object).slice(8, -1);
}

shouldBe('document.cloneNode(false).__proto__', 'HTMLDocument.prototype');
shouldBeEqualToString('className(document.cloneNode(false))', 'HTMLDocument');
shouldBe('document.cloneNode(true).title', 'document.title');
shouldBeEqualToString('document.cloneNode(true).compatMode', 'BackCompat');
shouldBeEqualToString('document.cloneNode(true).contentType', 'text/html');

var doc = document.implementation.createHTMLDocument('title');
shouldBe('doc.cloneNode(false).__proto__', 'HTMLDocument.prototype');
shouldBeEqualToString('className(doc.cloneNode(false))', 'HTMLDocument');
shouldBe('doc.cloneNode(true).title', 'doc.title');
shouldBeEqualToString('doc.cloneNode(true).compatMode', 'CSS1Compat');
shouldBeEqualToString('doc.cloneNode(true).contentType', 'text/html');

</script>
</body>