chromium/third_party/blink/web_tests/external/wpt/css/css-anchor-position/anchor-position-dynamic-003.html

<!DOCTYPE html>
<title>Tests that anchor layout changes in another BFC cause relayout on the anchored element</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-1/#propdef-anchor-name">
<link rel="author" href="mailto:[email protected]">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/check-layout-th.js"></script>
<script src="support/test-common.js"></script>
<style>
.containing-block {
  position: absolute;
}
.anchor {
  anchor-name: --a1;
  width: 50px;
  height: 70px;
  background: orange;
}
.after .anchor {
  width: 70px;
  height: 50px;
}
.target {
  position: absolute;
  left: anchor(--a1 right);
  top: anchor(--a1 bottom);
  width: anchor-size(--a1 width);
  height: anchor-size(--a1 height);
  background: green;
}

/* Various types of BFC as the containing block of the anchor */
.float {
  float: left;
}
.table {
  display: table;
}
.inline-block {
  display: inline-block;
  vertical-align: bottom;
}
.contain {
  contain: layout;
}
.scroller {
  overflow: scroll;
  width: 20px;
  height: 20px;
}
</style>
<body>
  <div class="containing-block">
    <div class="float">
      <div class="anchor"></div>
    </div>
    <div class="target"></div>
  </div>

  <div class="containing-block">
    <div class="table">
      <div class="anchor"></div>
    </div>
    <div class="target"></div>
  </div>

  <div class="containing-block">
    <div class="inline-block">
      <div class="anchor"></div>
    </div>
    <div class="target"></div>
  </div>

  <div class="containing-block">
    <div class="contain">
      <div class="anchor"></div>
    </div>
    <div class="target"></div>
  </div>

  <div class="containing-block">
    <div class="scroller">
      <div class="anchor"></div>
    </div>
    <div class="target"></div>
  </div>

<script type="module">
for (const element of document.getElementsByClassName('target')) {
  element.dataset.offsetX = '50';
  element.dataset.offsetY = '70';
  element.dataset.expectedWidth = '50';
  element.dataset.expectedHeight = '70';
}
await checkLayoutForAnchorPos('.target', false);

document.body.classList.add('after');
for (const element of document.getElementsByClassName('target')) {
  element.dataset.offsetX = '70';
  element.dataset.offsetY = '50';
  element.dataset.expectedWidth = '70';
  element.dataset.expectedHeight = '50';
}
await checkLayoutForAnchorPos('.after .target', true);
</script>
</body>