### Question:
OntologyHelper { public OWLClass getOwlClass(String iri) { OWLClass ret = null; if (StringUtils.isNotBlank(iri)) { ret = owlClassMap.get(IRI.create(iri)); } return ret; } OntologyHelper(OntologySettings config);  OntologyHelper(URI ontologyUri, OntologySettings config); void dispose(); OWLClass getOwlClass(String iri); Collection<String> findLabels(OWLClass owlClass); Collection<String> findLabelsForIRIs(Collection<String> iris); Collection<String> findSynonyms(OWLClass owlClass); Collection<String> findDefinitions(OWLClass owlClass); Collection<String> getChildUris(OWLClass owlClass); Collection<String> getDescendantUris(OWLClass owlClass); Collection<String> getParentUris(OWLClass owlClass); Collection<String> getAncestorUris(OWLClass owlClass); Map<String, List<String>> getRestrictions(OWLClass owlClass); void updateLastCallTime(); long getLastCallTime(); Set<String> getRestrictionProperties();  }### Answer:
@Test public void construct() throws Exception { OntologySettings settings = new OntologySettings(); settings.setOntologyUri(testOntologyUri.toString()); OntologyHelper helper = new OntologyHelper(settings); assertNotNull(helper.getOwlClass(TEST_IRI)); }
@Test(expected=java.lang.NullPointerException.class) public void construct_withNullUri() throws Exception { OntologySettings settings = new OntologySettings(); OntologyHelper helper = new OntologyHelper(settings); assertNotNull(helper.getOwlClass(TEST_IRI)); }