position-absolute-dynamic-static-position-flex.html

<!DOCTYPE html>
<link rel="match" href="../reference/ref-filled-green-100px-square.xht">
<link rel="help" href="https://www.w3.org/TR/css-position-3/" />
<meta name="assert" content="This test checks that a dynamic change in constraints calculates the static position correctly for flex children."/>
<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
<div style="display: flex; position: relative; width: 100px; height: 100px; background: red; align-items: flex-end;">
  <div id="target" style="position: absolute; width: 100px; height: 100px; background: green; bottom: 100px;"></div>
</div>
<script>
  document.body.offsetTop;
  document.getElementById('target').style.bottom = 'initial';
</script>

chromium/third_party/blink/web_tests/external/wpt/css/css-position/position-absolute-dynamic-static-position-flex.html