chromium/third_party/blink/web_tests/editing/inserting/5685601-1.html

<p>This tests for a bug where hitting return in an editable root that contains only a place holder would add two paragraph instead of one.  Below you should see an empty paragraph followed by one that contains only 'x'.</p>
<div id="div" contenteditable="true"><br></div>

<script>
div = document.getElementById("div");
div.focus();
document.execCommand("InsertParagraph");
document.execCommand("InsertText", false, "x");
if (window.testRunner) {
    testRunner.dumpAsText();
    document.body.innerText = div.innerHTML;
}
</script>