@Test
 public void shouldHandleNullManager_For_GetTopDataPropertyNode() {
   try {
     when(ontology.getOWLOntologyManager()).thenReturn(null);
     reasoner.getTopDataPropertyNode();
   } catch (NullPointerException e) {
     fail("NullPointerException");
   }
 }
 @Test
 public void shouldGetTopDataPropertyNode() {
   Node<OWLDataProperty> node = reasoner.getTopDataPropertyNode();
   assertThat(node.getEntities(), is(Collections.singleton(owlTopDataProperty)));
 }