chromium/src/third_party/blink/web_tests/compositing/geometry/flipped-blocks-inline-mapping.html

<style>
    .container {
      -webkit-writing-mode: vertical-rl;
      height: 100px;
      border: 1px solid black;
    }
    div {
      height: 20px;
    }
    .box {
      width: 20px;
      height: 20px;
      background-color: blue;
    }

    .transformed {
      will-change: transform;
    }
    span {
      opacity: 0.8;
    }
</style>
<div class="container">
    <span>
        <div class="transformed box"></div>
        <div style="display: inline-block">This test should not assert in debug builds</div>
    </span>
</div>
<script>
if (window.testRunner)
  testRunner.dumpAsText();
</script>