chromium/third_party/blink/web_tests/external/wpt/css/css-contain/content-visibility/content-visibility-053.html

<html>
<meta charset="utf8">
<title>Content Visibility: focus on display none element</title>
<link rel="author" title="Rakina Zata Amni" href="mailto:[email protected]">
<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
<meta name="assert" content="tab navigation skips display none elements in an auto subtree">

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

<div id=spacer style="height: 3000px"></div>
<div id="host">
  <input id="slotted" type="text">
</div>

<script>
test(() => {
  const container = document.createElement("div");
  container.innerHTML = "<slot></slot>";
  container.style = "content-visibility: auto";

  const shadowRoot = host.attachShadow({ mode: "open" });
  shadowRoot.appendChild(container);

  assert_not_equals(document.activeElement, slotted);
  slotted.focus();
  assert_equals(document.activeElement, slotted);
}, "Targetting a slotted auto-hidden element with focus makes it the active element");
</script>
</html>