mozilla-release/layout/reftests/floats/zero-height-float-base.html

<!DOCTYPE HTML>
    <title>CSS 2.1 Test Suite: wrapping around zero-height floats</title>
    <link rel="author" title="L. David Baron" href="https://dbaron.org/" />
    <link rel="author" title="Mozilla Corporation" href="http://mozilla.com/" />
    <link rel="help" href="http://www.w3.org/TR/CSS21/visuren.html#floats"/>
    <meta name="flags" content="" />
    <meta name="assert" content="wrapping around zero-height floats" />

<div style="width: 500px; height: 500px; float: left; font-size: 12px;">

  <div style="float: left; width: 10px; height: 30px"></div>
  <div style="float: left; clear: left; width: 100px; height: 1px"></div>

  <span style="display:inline-block; vertical-align: bottom; height: 20px; width: 300px; background: blue;"></span>
  <span style="display:inline-block; vertical-align: bottom; height: 20px; width: 300px; background: purple;"></span>
  <span style="display:inline-block; vertical-align: bottom; height: 20px; width: 300px; background: fuchsia"></span>

</div>