 testElement.root.querySelector('#projected');
  assert.equal(projected.textContent, 'projected');
  var rere = testElement.root.querySelector('x-rereproject');
  assert.equal(rere.is, 'x-rereproject');
  var re = rere.root.querySelector('x-reproject');
  assert.equal(re.is, 'x-reproject');
  var p = re.root.querySelector('x-project');
  assert.equal(p.is, 'x-project');
  var c1 = rere.root.querySelector('slot');
  assert.include(c1.assignedNodes({flatten: true}), projected);
  var c2 = re.root.querySelecto