css/css-values/rlh-invalidation.html

<!DOCTYPE html>
<title>CSS Values and Units Test: rlh invalidation</title>
<link rel="author" title="Daniil Sakhapov" href="sakhapov@google.com">
<link rel="help" href="https://drafts.csswg.org/css-values/#font-relative-lengths">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<meta name="assert" content="test rlh invalidation">
<style>
  @import url("/fonts/ahem.css");
  html {
    font-family: 'Ahem';
    font-size: 40px;
    line-height: 2;
  }
  body {
    font-family: monospace;
    font-size: 20px;
    line-height: 5;
  }
  div {
    width: 10rlh;
  }
</style>

<html>
  <body>
    <div id="div"></div>
  </body>
</html>

<script>
  setup({ single_test: true });
  let old_width = div.getBoundingClientRect().width;
  document.documentElement.style.lineHeight = "4";
  let new_width = div.getBoundingClientRect().width;
  assert_not_equals(old_width, new_width, "expect rlh units to update on line-height update");
  old_width = new_width;
  document.documentElement.style.fontSize = "41px";
  new_width = div.getBoundingClientRect().width;
  assert_not_equals(old_width, new_width, "expect rlh units to update on font-size update");
  done();
</script>