css/css-text/white-space/white-space-vs-joiners-001.html

<!DOCTYPE html>
<meta charset=utf-8>

<title>CSS Text Test: join controls do not disrupt white-space processing</title>
<link rel="author" title="Jonathan Kew" href="mailto:jkew@mozilla.com">
<link rel="help" href="https://drafts.csswg.org/css-text-3/#white-space-rules">
<!-- NB: The spec doesn't explicitly discuss join controls in this context,
     but it is self-evident that they should not have any effect on the white-space processing.
     Their only effect should be on the shaping (if any) of the adjacent characters. -->
<link rel="match" href="reference/white-space-vs-joiners-001-ref.html">
<meta name="assert" content="The presence of join controls (ZWJ/ZWNJ) at word edges should not affect white-space processing">

<style>
p {
  width: fit-content;
  border: 2px solid green;
  font: 24px monospace;
}
</style>

<body>
</body>

<script>
for (i = 0x200b; i <= 0x200f; ++i) {
  txt = "  "
    + String.fromCharCode(i)
    + "This should have no leading or trailing ["
    + i.toString(16)
    + "]"
    + String.fromCharCode(i)
    + "  ";
  p = document.createElement("p");
  p.textContent = txt;
  document.body.appendChild(p);
}
</script>