<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-anchor-1/#anchor-pos">
<link rel="author" href="mailto:kojii@chromium.org">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
.cb {
  position: relative;
  border-bottom: 2px solid gray;
}
.not-positioned-cb {
  transform: translate(0, 0);  /* Make it a containing block. */
}
.scroller { overflow: scroll; }
.borders { border-width: 5px 6px 7px 8px; border-style: solid; }
.spacer {
  height: 9px;
}
.anchor1 {
  anchor-name: --a1;
  margin-right: 50px;
  width: 31px;
  height: 31px;
  background: red;
}
.target {
  position: absolute;
  left: anchor(--a1 left);
  right: anchor(--a1 right);
  top: anchor(--a1 top);
  bottom: anchor(--a1 bottom);
  background: lime;
}
</style>
<body>
  <div class="spacer"></div>
  <div class="cb scroller" dir="rtl">
    <div class="spacer"></div>
    <div class="anchor1"></div>
    <div class="target"></div>
  </div>
  <div class="cb scroller borders" dir="rtl">
    <div class="spacer"></div>
    <div class="anchor1"></div>
    <div class="target"></div>
  </div>
  <div class="cb">
    <div class="scroller borders" dir="rtl">
      <div class="spacer"></div>
      <div class="anchor1"></div>
    </div>
    <div class="target"></div>
  </div>
  <div class="cb scroller borders" dir="rtl">
    <div class="not-positioned-cb">
      <div class="spacer"></div>
      <div class="anchor1"></div>
    </div>
    <div class="target"></div>
  </div>
  <div class="cb scroller borders" dir="rtl">
    <div class="not-positioned-cb scroller borders">
      <div class="spacer"></div>
      <div class="anchor1"></div>
    </div>
    <div class="target"></div>
  </div>
<script>
function getBoundingClientRectAsArray(element) {
  const rect = element.getBoundingClientRect();
  return [rect.left, rect.top, rect.right, rect.bottom];
}

const anchors = document.getElementsByClassName('anchor1');
const targets = document.getElementsByClassName('target');
for (let i = 0; i < targets.length; ++i) {
  test(() => {
    const anchor = anchors[i];
    const target = targets[i];
    assert_array_equals(getBoundingClientRectAsArray(anchor),
                        getBoundingClientRectAsArray(target));
  });
}
</script>
</body>
