chromium/third_party/blink/web_tests/fast/css-generated-content/pseudo-triple-click.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Pseudo-Elements Test: Triple-click</title>
<link rel="help" href="https://drafts.csswg.org/css-pseudo-4/#treelike">
<link rel="help" href="https://drafts.csswg.org/css-ui/#user-interaction">
<link rel="author" title="Oriol Brufau" href="mailto:[email protected]">
<meta name="assert" content="This test checks that there is no crash when triple-clicking a pseudo-element that is destroyed when focused." />
<style>
.target {
  width: max-content;
  font: 50px/1 Ahem;
}
[data-pseudo="::marker"]:not(:focus) {
  display: list-item;
  list-style-type: 'XX';
  direction: rtl;
}
[data-pseudo="::before"]:not(:focus)::before {
  display: inline-block;
  content: 'XX';
}
[data-pseudo="::after"]:not(:focus)::after {
  display: inline-block;
  content: 'XX';
}
</style>
<div class="target" data-pseudo="::marker" contenteditable="true"></div>
<div class="target" data-pseudo="::before" contenteditable="true"></div>
<div class="target" data-pseudo="::after" contenteditable="true"></div>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script src="../../resources/user-gesture-utils.js"></script>
<script>
for (let target of document.querySelectorAll(".target")) {
  const {pseudo} = target.dataset;
  test(function(t) {
    const x = target.offsetLeft + 50;
    const y = target.offsetTop + target.offsetHeight / 2;

    // The pseudo-element generates a 100px wide box
    assert_equals(getComputedStyle(target, pseudo).width, "100px", "initial width");

    // Click in the middle of #target
    simulateUserClick(x, y);

    // #target is now focused, and the pseudo-element has been destroyed
    assert_equals(getComputedStyle(target, pseudo).width, "auto", "width after click");

    // Triple-click in the same location
    simulateUserClick(x, y);
    simulateUserClick(x, y);
    simulateUserClick(x, y);

    // We haven't crashed
  }, pseudo);
}
</script>