@Override
  public boolean offerFirst(T t)
  {
    addFirstNode(t);
    return true;
  }
@Test
  public void testOfferFirst()
  {
    List<Integer> control = new ArrayList<>(Arrays.asList(1, 2, 3));
    LinkedDeque<Integer> q = new LinkedDeque<>(control);

    control.add(0, 99);
    Assert.assertTrue(q.offerFirst(99));

    Assert.assertEquals(q, control);
  }