chromium/third_party/blink/web_tests/editing/pasteboard/5780697-1.html

<html>
<head>
<style>
p {
    color: red;
}
</style>
</head>
<body>
<div id="description">This tests for a copy bug where styles from matched rules would be placed on elements and take precedence over styles from their inline style declarations. When run manually, you must do a Paste.  The text in the bottom region should be blue.</div>
<div id="copy" contenteditable="true">
<p style="color: blue;">This text</p>
<p style="color: blue;">should be</p>
<p style="color: blue;">blue</p>
</div>

<div id="paste" contenteditable="true"></div>

<script>
copy = document.getElementById("copy");
copy.focus();
document.execCommand("selectall");
document.execCommand("copy");
paste = document.getElementById("paste");
paste.focus();
document.execCommand("paste");
if (window.testRunner) {
    testRunner.dumpAsText();
    document.body.innerText = document.getElementById("description").innerText + "\n\n" + copy.innerHTML;
}
</script>
</body>
</html>