chromium/third_party/blink/web_tests/fast/multicol/span/float.html

<!DOCTYPE html>
<p>Test that a float inside a spanner stretches an auto-height spanner, since the spanner is
    supposed to establish a new block formatting context.</p>
<p>Below you should see a green square, followed by the word 'PASS' (with large letter spacing), and no red.</p>
<div style="width:5em; -webkit-columns:1em; -webkit-column-gap:0; orphans:1; widows:1;">
    <div style="-webkit-column-span:all; background:red;">
        <div style="float:left; width:100%; height:5em; background:green;"></div>
    </div>
    P<br>
    A<br>
    S<br>
    S<br>
</div>