chromium/third_party/blink/web_tests/external/wpt/css/css-contain/contain-size-select-002.html

<!DOCTYPE html>
<html class="reftest-wait">
<meta charset="utf-8">
<title>CSS Containment Test: Size containment on select</title>
<link rel="author" title="Manuel Rego Casasnovas" href="mailto:[email protected]">
<link rel="help" href="https://drafts.csswg.org/css-contain-1/#containment-size">
<link rel="match" href="reference/contain-size-select-001-ref.html">
<meta name=assert content="Check that setting 'contain: size' on a <select> elements causes it to be sized as having no contents.">
<style>
select {
  color: transparent;
  background: white;
}
</style>
<p>Test passes if it has the same output than the reference.</p>
<select id="target">
  <option>AVeryLongOption</option>
  <option>Another Option</option>
</select>
<script>
  window.requestAnimationFrame( () => {
    target.style.contain = "size";
    document.documentElement.removeAttribute("class");
  });
</script>
</html>