<!DOCTYPE html>
<meta charset="utf-8">
<title>HTML Test: DocumentOrShadowRoot.activeElement</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<body>
<script>
function createChildAndFocus(focusParent) {
  const focused = document.createElement("div");
  focused.tabIndex = 0;
  focusParent.appendChild(focused);
  focused.focus();
  return focused;
}

test(() => {
  const host = document.createElement("div");
  const shadowRoot = host.attachShadow({ mode: "open" });
  document.body.appendChild(host);

  const focused = createChildAndFocus(shadowRoot);
  assert_equals(document.activeElement, host);
  assert_equals(shadowRoot.activeElement, focused);
}, "activeElement on document & shadow root when focused element is in the shadow tree");

test(() => {
  const host = document.createElement("div");
  const shadowRoot = host.attachShadow({ mode: "open" });
  document.body.appendChild(host);

  const focused = createChildAndFocus(document.body);
  assert_equals(document.activeElement, focused);
  assert_equals(shadowRoot.activeElement, null);
}, "activeElement on document & shadow root when focused element is in the document");

test(() => {
  const host = document.createElement("div");
  const shadowRoot = host.attachShadow({ mode: "open" });
  shadowRoot.appendChild(document.createElement("slot"));
  document.body.appendChild(host);

  // Child of |host|, will be slotted to the slot in |shadowRoot|.
  const focused = createChildAndFocus(host);
  assert_equals(document.activeElement, focused);
  assert_equals(shadowRoot.activeElement, null);
}, "activeElement on document & shadow root when focused element is slotted");

test(() => {
  const host = document.createElement("div");
  const shadowRoot = host.attachShadow({ mode: "open" });
  document.body.appendChild(host);
  const neighborHost = document.createElement("div");
  const neighborShadowRoot = neighborHost.attachShadow({ mode: "open" });
  document.body.appendChild(neighborHost);

  const focused = createChildAndFocus(shadowRoot);
  assert_equals(document.activeElement, host);
  assert_equals(shadowRoot.activeElement, focused);
  assert_equals(neighborShadowRoot.activeElement, null);
}, "activeElement on a neighboring host when focused element is in another shadow tree");

test(() => {
  const host = document.createElement("div");
  const shadowRoot = host.attachShadow({ mode: "open" });
  document.body.appendChild(host);
  const nestedHost = document.createElement("div");
  const nestedShadowRoot = nestedHost.attachShadow({ mode: "open" });
  shadowRoot.appendChild(nestedHost);

  const focused = createChildAndFocus(nestedShadowRoot);
  assert_equals(document.activeElement, host);
  assert_equals(shadowRoot.activeElement, nestedHost);
  assert_equals(nestedShadowRoot.activeElement, focused);
}, "activeElement when focused element is in a nested shadow tree");

test(() => {
  const host = document.createElement("div");
  const shadowRoot = host.attachShadow({ mode: "open" });
  document.body.appendChild(host);
  const nestedHost = document.createElement("div");
  const nestedShadowRoot = nestedHost.attachShadow({ mode: "open" });
  shadowRoot.appendChild(nestedHost);

  const focused = createChildAndFocus(shadowRoot);
  assert_equals(document.activeElement, host);
  assert_equals(shadowRoot.activeElement, focused);
  assert_equals(nestedShadowRoot.activeElement, null);
}, "activeElement when focused element is in a parent shadow tree");
</script>
</body>