chromium/third_party/blink/web_tests/external/wpt/css/css-text/text-transform/text-transform-fullwidth-006.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Text level 3 Test: text-transform:fullwidth and collapsed spaces</title>
<link rel="author" title="Florian Rivoal" href="https://florian.rivoal.net/">
<link rel="help" href="https://www.w3.org/TR/css-text-3/#text-transform-property">
<link rel="match" href="reference/text-transform-fullwidth-006-ref.html">
<meta name="assert" content="full-width does not transform collapsed U+0020 spaces to U+3000, only the remaining one after collapsing.">
<link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
<style>
div { font: 50px/1 Ahem; }
#test {
  color: green;
}
span {
  text-transform: full-width;
}
#ref {
  color: red;
  position: absolute;
  z-index: -1;
}
</style>

<p>Test passes if there are two green squares and no red.
<div id=ref>x&#x3000;x</div>
<div id=test>x<span>   </span>x</div>