chromium/third_party/blink/web_tests/external/wpt/css/css-flexbox/hittest-overlapping-margin.html

<!DOCTYPE html>
<link rel="author" title="Andrew Comminos" href="mailto:[email protected]" />
<link rel="help" href="http://www.w3.org/TR/css-flexbox-1/#painting" />
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
#container {
  width: 600px;
  display: flex;
}

#left {
  width: 300px;
  overflow: hidden;
  white-space: nowrap;
  background: rgba(200, 200, 200, 0.8);
}

#right {
  width: 300px;
  background-color: rgba(0, 128, 0, 0.8);
  margin-left: -100px;
}
</style>
<div id="container">
  <a id="left" href="#">foofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoofoo</a>
  <div id="right"></div>
</div>
<div id="log"></div>
<script>
  test(function(t)
    {
      const container = document.querySelector('#container');
      // Target the intersection of the two child elements.
      // The occluded link should not be clickable.
      const x = container.offsetLeft + 250;
      const y = container.offsetTop + 5;

      var element = document.elementFromPoint(x, y);
      assert_equals(element.nodeName, 'DIV');
      assert_equals(element.id, 'right');
    }, "Flexboxes should perform hit testing in reverse paint order for overlapping elements: negative margin case (crbug.com/844505)");
</script>