<!DOCTYPE html>
<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
<link rel="help" href="https://www.w3.org/TR/css-multicol-1/#cf">
<p>Test passes if there is a filled green square.</p>
<div id="mc" style="columns:10; background:green;">
  <div>
    <div style="height:100px; contain:size;"></div>
    <div style="break-before:column;"></div>
  </div>
</div>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
  test(()=> {
    assert_equals(mc.offsetHeight, 100);
  });
</script>
