pse
  with the bottom margin of its last in-flow child if `height` computes
  to `auto`.

  However, according to CSS Sizing, that was 'legacy spec prose' and
  should be interpreted as 'behaves as `auto`'.

  Therefore, an indefinite `stretch` in the preferred block size property
  shouldn't prevent margin collapse, because it behaves as `auto`.
">

<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
<div style="width: 100px; height: stretch; background: red">
  <div style="he