chromium/third_party/blink/web_tests/fast/multicol/nested-short-first-row-unsplittable-block.html

<!DOCTYPE html>
<script src="../../resources/check-layout.js"></script>
<p>The word "YO" should be seen below.</p>
<div id="outer" style="position:relative; -webkit-column-count:3; -webkit-column-gap:0; column-fill:auto; font-size:16px; width:9em; height:5em; text-align:right;">
    <div data-offset-x="0" data-offset-y="0">Y</div>
    <div style="-webkit-column-count:3; -webkit-column-gap:0;">
        <div></div>
        <div data-offset-x="48" data-offset-y="0" style="-webkit-column-break-inside:avoid; height:4em;">O</div>
    </div>
</div>
<script>
    checkLayout("#outer");
</script>