css/cssom-view/scrollIntoView-shadow.html

<!DOCTYPE HTML>
<meta name="viewport" content="user-scalable=no">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<title>Check End Position of scrollIntoView of shadow elements</title>
<div id="container">
  <div id="space1" style="height: 2000px; width: 2000px;background-color: yellow">
  </div>
  <div id="shadow"></div>
  <div id="space2" style="height: 2000px; width: 2000px;background-color: blue">
  </div>
</div>
<script>
add_completion_callback(() => document.getElementById("container").remove());

test(t => {
  var shadow = document.getElementById("shadow");
  var shadowRoot = shadow.attachShadow({ mode: "open" });
  var shadowDiv = document.createElement("div");
  shadowDiv.style.height = "200px";
  shadowDiv.style.width = "200px";
  shadowDiv.style.backgroundColor = "green";
  shadowRoot.appendChild(shadowDiv);

  window.scrollTo(0, 0);
  var expected_x = shadowDiv.offsetLeft;
  var expected_y = shadowDiv.offsetTop;
  assert_not_equals(window.scrollX, expected_x);
  assert_not_equals(window.scrollY, expected_y);
  shadowDiv.scrollIntoView({block: "start", inline: "start"});
  assert_approx_equals(window.scrollX, expected_x, 1);
  assert_approx_equals(window.scrollY, expected_y, 1);
}, "scrollIntoView should behave correctly if applies to shadow dom elements");
</script>