self-collapsing-block-with-overflow-hidden-and-float-child.html

<!DOCTYPE html5>
<html>
<style>
.outside {  
  margin-top: 20px;
  overflow: hidden;
  background: #ddd;
}

.inside {
  float: left;
  background: #fff;
  width: 100px;
  height: 100px;
  margin: 10px;
}
</style>
<script>
    if (window.testRunner)
        testRunner.dumpAsText();
</script>
<p> https://bugs.webkit.org/show_bug.cgi?id=106374: The top of the two white boxes below should be aligned. </p>
<div class="outside">
    <div id="first" class="inside"></div>
    <div id="second" class="inside"></div>
</div>
<div id="console"></div>
<script>
    if (document.getElementById("first").offsetTop == document.getElementById("second").offsetTop)
        document.getElementById("console").innerText = "PASSED";
    else
        document.getElementById("console").innerText = "FAILED";
</script>
</html>

chromium/third_party/blink/web_tests/fast/block/margin-collapse/self-collapsing-block-with-overflow-hidden-and-float-child.html