chromium/third_party/blink/web_tests/external/wpt/css/css-pseudo/selection-originating-underline-order.html

<!doctype html>
<meta charset="utf-8">
<!-- see “Selection regression tests” in README.md -->
<title>CSS Pseudo-Elements Test: originating underlines remain under unselected parts when selecting text</title>
<link rel="author" name="Delan Azabani" href="mailto:[email protected]">
<link rel="help" href="https://drafts.csswg.org/css-pseudo-4/#highlight-painting">
<link rel="help" href="https://drafts.csswg.org/css-text-decor-4/#painting">
<link rel="help" href="https://www.w3.org/TR/CSS22/zindex.html#painting-order">
<link rel="match" href="selection-originating-underline-order-ref.html">
<meta name="assert" value="This test verifies that selecting text does not cause originating underline decorations, which should always paint under text, to paint over unselected parts.">
<script src="support/selections.js"></script>
<link rel="stylesheet" href="support/highlights.css">
<link rel="stylesheet" href="/fonts/ahem.css">
<style>
    * {
        text-decoration-skip-ink: none;
        text-decoration-skip: none;
    }
    main {
        font: 80px/1 Ahem;
        margin: 0.5em;
        width: min-content;
        text-decoration: 0.25em red solid underline;
        /* try to keep decoration between ascent and descent */
        text-underline-offset: -0.5em;
    }
    main::selection {
        background: transparent;
        color: blue;
    }
</style>
<p>Test passes if there is no red below and two squares, entirely blue (left) and entirely black (right).
<main class="highlight_reftest">XX</main>
<script>
    const target = document.querySelector("main");
    selectRangeWith(range => {
        range.selectNodeContents(target);
        range.setStart(target.childNodes[0], 0);
        range.setEnd(target.childNodes[0], 1);
    });
</script>