<!DOCTYPE html>
<meta name="author" title="Xiaocheng Hu" href="mailto:xiaochengh@chromium.org">
<meta name="assert" content="User code can attach CustomElementRegistry to ShadowRoot">
<link rel="help" href="https://wicg.github.io/webcomponents/proposals/Scoped-Custom-Element-Registries">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<body>
<script>
function createShadowHost(testObject) {
  let element = document.createElement('div');
  testObject.add_cleanup(() => element.remove());
  document.body.appendChild(element);
  return element;
}

test(function() {
  let host = createShadowHost(this);
  let shadow = host.attachShadow({mode: 'open'});
  assert_equals(shadow.registry, null);
}, 'ShadowRoot.registry is null if not explicitly specified');

test(function() {
  let host = createShadowHost(this);
  let shadow = host.attachShadow({mode: 'open', registry: window.customElements});
  assert_equals(shadow.registry, window.customElements);
}, 'Attach the global registry to a shadow root');

test(function() {
  let host = createShadowHost(this);
  let registry = new CustomElementRegistry();
  let shadow = host.attachShadow({mode: 'open', registry});
  assert_equals(shadow.registry, registry);
}, 'Attach a non-global registry to a shadow root');

test(function() {
  let registry = new CustomElementRegistry();
  let host1 = createShadowHost(this);
  let shadow1 = host1.attachShadow({mode: 'open', registry});
  let host2 = createShadowHost(this);
  let shadow2 = host2.attachShadow({mode: 'open', registry});
  assert_equals(shadow1.registry, registry);
  assert_equals(shadow2.registry, registry);
}, 'Attach the same registry to multiple shadow roots');

test(function() {
  let host = createShadowHost(this);
  let shadow = host.attachShadow({mode: 'open'});
  shadow.registry = new CustomElementRegistry();
  assert_equals(shadow.registry, null);
}, 'Attaching registry to shadow root can only be done during initialization');
</script>
</body>
