extSibling, null, 'nextSibling incorrect');
    assert.equal(element.previousSibling, null, 'previousSibling incorrect');
    assert.equal(element.firstElementChild, child1, 'firstElementChild incorrect');
    assert.equal(element.lastElementChild, child2, 'lastElementChild incorrect');
    assert.equal(element.nextElementSibling, null, 'nextElementSibling incorrect');
    assert.equal(element.previousElementSibling, null, 'previousElementSibling incorrect');
  });

  test('textContent', function() {
    va