<!DOCTYPE html>
<title>translations on position:sticky elements should apply after sticking</title>
<link rel="help" href="https://www.w3.org/TR/css-position-3/#sticky-pos" />
<meta name="assert" content="This test checks that translations on position:sticky elements are carried out on their stuck position" />

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<script src="../resources/sticky-util.js"></script>

<body style="margin: 0;"></body>

<script>
test(() => {
  const elements = setupStickyTest('top', 50);
  elements.sticky.style.transform = 'translateY(-100%)';
  elements.scroller.scrollTop = 100;
  // Transforms don't affect offsetTop, so use getBoundingClientRect.
  assert_equals(elements.sticky.getBoundingClientRect().y,
      elements.scroller.getBoundingClientRect().y);
}, 'Translation transform can move sticky element past sticking point');

test(() => {
  const elements = setupStickyTest('top', 50);
  elements.sticky.style.transform = 'translateY(50%)';
  elements.scroller.scrollTop = 200;
  // Transforms don't affect offsetTop, so use getBoundingClientRect.
  const stickyElementOffset = elements.sticky.getBoundingClientRect().y -
      elements.scroller.getBoundingClientRect().y;
  assert_equals(stickyElementOffset, 100);
}, 'Stuck elements can still be moved via translations');

test(() => {
  const elements = setupStickyTest('top', 50);
  elements.container.style.transform = 'translateY(100px)';
  elements.scroller.scrollTop = 200;
  // Transforms don't affect offsetTop, so use getBoundingClientRect.
  // Here the sticky element will originally have stuck at 50px from the top,
  // but is then 'pulled' downwards by the 100px container transform.
  const stickyElementOffset = elements.sticky.getBoundingClientRect().y -
      elements.scroller.getBoundingClientRect().y;
  assert_equals(stickyElementOffset, 150);
}, 'The sticky element should stick before the container is offset by a ' +
    'translation');
</script>
