css/cssom/getComputedStyle-property-order.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSSOM: getComputedStyle property order</title>
<link rel="help" href="https://drafts.csswg.org/cssom/#dom-window-getcomputedstyle">
<link rel="author" title="Oriol Brufau" href="mailto:obrufau@igalia.com">
<meta name="assert" content="This test checks that in a computed style, properties are sorted in lexicographical order." />
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<script>
test(function() {
  const properties = [...getComputedStyle(document.documentElement)];
  const sorted = properties.slice().sort(function(a,b) {
    if (a === b) {
      assert_unreached("There shouldn't be repeated properties");
      return 0;
    }
    // Sort vendor-prefixed properties after standard ones
    if (a.startsWith("-") != b.startsWith("-")) {
      return b.startsWith("-") ? -1 : 1;
    }
    // Sort with lexicographical order
    return a < b ? -1 : 1;
  });
  assert_array_equals(properties, sorted);
}, "Computed style properties should be sorted lexicographically");
</script>