chromium/third_party/blink/web_tests/external/wpt/css/css-writing-modes/tcy-white-space-processing-003.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Writing Modes Test: white space only text-combine-horizontal</title>
<link rel="author" title="Florian Rivoal" href="https://florian.rivoal.net">
<link rel="help" href="https://www.w3.org/TR/css-writing-modes-4/#text-combine-layout">
<link rel="help" href="https://drafts.csswg.org/css-text-3/#white-space-rules">
<link rel="match" href="reference/tcy-white-space-processing-003-ref.html">
<meta name="assert" content="a text-combine-upright with only white-space is preserved as a 1em square, including at the end of the containing line, regardless of the value of the white-space property">
<style>
.v-rl {
  writing-mode: vertical-rl;
  width: 200px;
}
#test span {
  -webkit-text-combine: horizontal; /*testing the layout text-combine, not it's support in general*/
  text-combine-upright: all;
}
#test2 span {
  -webkit-text-combine: horizontal; /*testing the layout text-combine, not it's support in general*/
  text-combine-upright: all;
  white-space: pre;
}
#ref span {
  display: inline-block;
  height: 1em;
}
#test { color: blue; }
#test2 { color: brown; }
#ref { color: orange; }
.v-rl > div {
  display: inline-block;
  border: solid;
  margin: 0 5px;
}
</style>
<p>Test passes if the blue, orange, brown boxes are identical.

<div class=v-rl>
  <div id=test>あいう<span> </span>えお<span> </span></div>
  <br>
  <div id=test2>あいう<span> </span>えお<span> </span></div>
  <br>
  <div id=ref>あいう<span></span>えお<span></span></div>
</div>