LayoutTests/fast/text/word-spacing-rtl-expected.html

<style>
div { 
  font-family: Ahem;
  font-size: 20px;
  width: 200px;
  white-space: pre;
  color: green;
}
</style>
<div style="direction: ltr;">X  X  X</div>
<div style="direction: rtl;">X  X  X</div>

<div style="direction: ltr;">XXX</div>
<div style="direction: rtl;">XXX</div>