chromium/third_party/blink/web_tests/external/wpt/css/css-highlight-api/painting/custom-highlight-painting-004-2.html

<!DOCTYPE html>
<meta charset="UTF-8">
<title>CSS Highlight API Test: </title>
<link rel="help" href="https://drafts.csswg.org/css-highlight-api-1/">
<link rel="match" href="custom-highlight-painting-004-2-ref.html">
<meta name="assert" value="When painting overlapping highlights with the same .priority, the one added last should be painted on top; and style properties not defined by the one on top (background-color in this case) should follow the rules of the next Highlight from top to bottom until there's one that overwrites default (or use default value otherwise).">
<meta name="fuzzy" content="0-88;0-4">
<style>
  ::highlight(foo) {
    color:blue;
    background-color:yellow;
  }
  ::highlight(bar) {
    color:orange;
  }
</style>
<body>Some text
<script>
  let textNode = document.body.firstChild;

  let r1 = new Range();
  r1.setStart(textNode, 0);
  r1.setEnd(textNode, 6);

  let r2 = new Range();
  r2.setStart(textNode, 3);
  r2.setEnd(textNode, 9);

  let h1 = new Highlight(r1);
  let h2 = new Highlight(r2);

  CSS.highlights.set("foo", h1);
  CSS.highlights.set("bar", h2);
</script>