<!DOCTYPE HTML>
<link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
<link rel="help" href="https://drafts.csswg.org/css-contain/#containment-size">
<link rel="help" href="https://bugs.chromium.org/p/chromium/issues/detail?id=863454">
<style>
  #flex {
    display: flex;
  }

  #multicol {
    columns: 3;
    min-width: 0;
    column-gap: 50px;
    contain:size;
    height:100px;
    background:green;
  }
</style>
<p>There should be a green square below.</p>
<div id="flex">
  <div id="multicol" data-expected-width="100" data-expected-height="100">
    <div style="width:1000px; height:1px;"></div>
  </div>
</div>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/check-layout-th.js"></script>
<script>
  checkLayout("#flex");
</script>