css/css-cascade/scope-hover.html

<!DOCTYPE html>
<title>@scope and :hover</title>
<link rel="help" href="https://drafts.csswg.org/css-cascade-6/#scope-atrule">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-actions.js"></script>
<script src="/resources/testdriver-vendor.js"></script>

<main id=main></main>

<script>
  async function hover(element) {
    let actions = new test_driver.Actions().pointerMove(0, 0, {origin: element});
    await actions.send();
  }
</script>

<template id=test_subject>
  <div>
    <style>
        @scope (.a:hover) {
          :scope { z-index: 1; }
        }
    </style>
    <div class=a>1</div>
</template>
<script>
promise_test(async (t) => {
  t.add_cleanup(() => main.replaceChildren());
  main.append(test_subject.content.cloneNode(true));
  let a = main.querySelector('.a');
  assert_equals(getComputedStyle(a).zIndex, 'auto');
  await hover(a);
  assert_equals(getComputedStyle(a).zIndex, '1');
}, ':hover via :scope in subject');
</script>

<template id=test_non_subject>
  <div>
    <style>
        @scope (.a:hover) {
          :scope .b { z-index: 1; }
        }
    </style>
    <div class=a>
      <div class=b>2</div>
    </div>
</template>
<script>
promise_test(async (t) => {
  t.add_cleanup(() => main.replaceChildren());
  main.append(test_non_subject.content.cloneNode(true));

  let a = main.querySelector('.a');
  let b = main.querySelector('.b');

  assert_equals(getComputedStyle(b).zIndex, 'auto');
  await hover(a);
  assert_equals(getComputedStyle(b).zIndex, '1');
}, ':hover via :scope in non-subject');
</script>

<template id=test_subject_limit>
  <div>
    <style>
        @scope (.a) to (:scope:hover) {
          :scope { z-index: 1; }
        }
    </style>
    <div class=a tabindex=0>3</div>
</template>
<script>
promise_test(async (t) => {
  t.add_cleanup(() => main.replaceChildren());
  main.append(test_subject_limit.content.cloneNode(true));

  let a = main.querySelector('.a');

  assert_equals(getComputedStyle(a).zIndex, '1');
  await hover(a);
  // After hover, we're no longer in scope because the limit (to-selector)
  // kicks in.
  assert_equals(getComputedStyle(a).zIndex, 'auto');
}, ':hover in limit, :scope in subject');
</script>

<template id=test_non_subject_limit>
  <div>
    <style>
        @scope (.a) to (.b:hover) {
          .b { z-index: 1; }
        }
    </style>
    <div class=a tabindex=0>
      <div class=b tabindex=1>4</div>
    </div>
</template>
<script>
promise_test(async (t) => {
  t.add_cleanup(() => main.replaceChildren());
  main.append(test_non_subject_limit.content.cloneNode(true));

  let a = main.querySelector('.a');
  let b = main.querySelector('.b');

  assert_equals(getComputedStyle(b).zIndex, '1');
  await hover(b);
  // After hover, we're no longer in scope because the limit (to-selector)
  // kicks in.
  assert_equals(getComputedStyle(b).zIndex, 'auto');
}, ':hover in intermediate limit, :scope in subject');
</script>