 content);
      assert.equal(ShadyDOM.nativeTree.nextSibling(content), srLast);
      assert.equal(ShadyDOM.nativeTree.previousSibling(srLast), content);
      assert.equal(ShadyDOM.nativeTree.previousSibling(content), srFirst);
      assert.deepEqual(Array.from(ShadyDOM.nativeTree.childNodes(el)), [srFirst, content, srLast])
    });

    test('element accessors', function() {
      let srFirst = el.shadowRoot.firstChild;
      let srLast = el.shadowRoot.lastChild;
      let content = el.firstChild;
      