chromium/third_party/blink/web_tests/external/wpt/css/css-text/word-space-transform/word-space-transform-018.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Text level 4 Test: word-space-transform: auto-phrase outermost placement</title>
<link rel="author" title="Florian Rivoal" href="http://florian.rivoal.net/">
<link rel="help" href="https://drafts.csswg.org/css-text-4/#word-space-transform">
<link rel="help" href="https://drafts.csswg.org/css-text-4/#word-phrase-detection">
<link rel="match" href="reference/word-space-transform-018-ref.html">
<meta name="assert" content="If a word/phrase boundary is found at the same position as one or more inline box boundaries, the virtual expandable separator must be inserted in the outermost element that participates in this inline box boundary.">
<style>
div {
  font-size: 2em;
  border: solid black;
  margin: 5px;
  width: 30ch;
}
#test {
  word-space-transform: space auto-phrase;
}
#ref {
  border-color: blue;
}
u {  background: silver; }
b {  background: green; }
em { background: gray; }
</style>

<p>Test passes if the black box is identical to the blue one.

<div id=test lang=th>กรุงเทพ<b><u>คือ</u><em>สวยง</em></b>าม</div>
<div id=ref lang=th>กรุงเทพ <b><u>คือ</u> <em>สวยง</em></b>าม</div>