LayoutTests/fast/ruby/ruby-base-with-breakable-content-inside.html

<style>
body {
  font-family: Ahem;
}
div {
  width: 10px;
}
rt {
  color: transparent;
}
</style>
<!-- PASS if X characters are right below each other -->
<div><ruby><rb><span>X X X</span></rb><rt>X</rt></ruby></div>