frame);
  iframe.contentDocument.adoptNode(span);
  iframe.contentDocument.body.appendChild(span);
  assert_not_equals(span.shadowRoot, null);
  assert_equals(span.shadowRoot.adoptedStyleSheets.length, 0);
  assert_equals(getComputedStyle(shadowDiv).color, "rgb(0, 0, 0)");
}, 'Adopting a shadow host will empty adoptedStyleSheets if adopting to a different document');

test(() => {
  const span = document.createElement("span");
  const div = document.createElement("div");
  thirdSection.appendChild(span);
  