<!DOCTYPE html>
<title>Declarative Shadow DOM with shadow disabled</title>
<link rel='author' href='mailto:masonf@chromium.org'>
<link rel='help' href='https://github.com/whatwg/dom/issues/831'>
<script src='/resources/testharness.js'></script>
<script src='/resources/testharnessreport.js'></script>

<body>
<script>
class ShadowDisabledElement extends HTMLElement {
  static get disabledFeatures() {
    return ['shadow'];
  }
}
customElements.define('shadow-disabled',ShadowDisabledElement);
</script>

<shadow-disabled>
  <template shadowrootmode="open"><span id=inside></span></template>
</shadow-disabled>

<script>
test(t => {
  let element = document.querySelector('shadow-disabled');
  assert_true(element instanceof ShadowDisabledElement);
  let template = element.querySelector('template');
  assert_true(!!template, 'Declarative shadow attach should fail, since shadow-disabled is true');
  assert_true(!element.shadowRoot, 'Shadow root should not be present on custom element');
}, 'Declarative Shadow DOM: declarative shadow should fail if attachShadow() already called');
</script>
</body>
