@Test
 public void shouldReturnSelfForAncestorOfDepthEqualToDepthOfNode() throws Exception {
   assertThat(altimaModel.getAncestor(altimaModel.getDepth()), is((Item) altimaModel));
   assertThat(altimaModel.getAncestor(altimaModel.getDepth() - 1), is((Item) altima));
 }