chromium/src/third_party/blink/web_tests/fast/dom/Range/13000.html

<p>This tests for a bug in Range::createContextualFragment, it would fail if the range started in a text node.  You should see 'The quick brown fox, jumps over the lazy dog" below.</p>
<div id="div" contenteditable="true">The , jumps over the lazy dog.</div>

<script>
if (window.testRunner)
    testRunner.dumpAsText();
    
var div = document.getElementById("div");
var text = div.firstChild;
var sel = window.getSelection();

sel.collapse(text, 4);
var range = sel.getRangeAt(0);
var html = "quick brown fox";
var frag = range.createContextualFragment(html);
range.insertNode(frag);
</script>