chromium/third_party/blink/web_tests/external/wpt/css/css-flexbox/flex-direction-column-overlap-001.html

<!DOCTYPE html>
<html>
<title>CSS Flexbox: vertical overlap with flex-direction: column.</title>
<link rel="help" href="https://drafts.csswg.org/css-flexbox/#flex-direction-property">
<link rel="help" href="https://crbug.com/669714"/>
<meta name="assert" content="This test ensures that no unnecessary vertical overlap happens between an inline flex item and a block element inside a nested flexbox with 'flex-direction: column'."/>

<style>
html {
  line-height: 1;
  font-size: 18px;
}

.flex {
  flex: 1;
  min-height: 0;
}

.layout-column, .layout-row {
  display: flex;
}

.layout-column {
  flex-direction: column;
}

#relpos {
  position: relative;
  top: 1px;
}
</style>

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/check-layout-th.js"></script>

<body>

<p>XXX and YYY should be on separate lines and not overlap, i.e. the height of .flex should not be 0.</p>

<div class="layout-column" id="container">
    <div class="layout-row">
      <div class="layout-column">
        <div class="flex" data-expected-height="18">XXX<span id="relpos"></span></div>
        <div>YYY</div>
      </div>
    </div>
</div>

<script>
document.body.offsetHeight;
document.getElementById("relpos").innerText = " ";
checkLayout("#container");
</script>
</body>
</html>