### Question:
JSONVocabularyHelper implements VocabularyHelper { @Override public List<List<String>> getAuthoritativeForm(String term) { if (values.contains(term)) { return Arrays.asList(Arrays.asList(term)); } return null; }  @Override List<List<String>> getAuthoritativeForm(String term); @Override List<List<String>> getAuthoritativeForms(Element docRoot); @Override Set<String> getInvalidTerms(Element docRoot); @Override Set<String> getInvalidTermsWithPrefix(Element docRoot); @Override boolean updateDocumentTerms(Element docElement); @Override Collection<String> getVocabularyTerms(); @Override void setSelector(String selector); @Override void setSelectorNamespaces(Namespace[] namespaces); @Override String getSelector(); void setInvalidTermPrefix(String prefix); @Override String getInvalidTermPrefix(); @Override String getVocabularyURI(); @Override void setVocabularyURI(String vocabularyURI); @Override void setContent(byte[] content);  }### Answer:
@Test public void getAuthoritativeFormTest() { List<List<String>> terms = helper.getAuthoritativeForm("Creator"); assertEquals("Creator", terms.get(0).get(0)); terms = helper.getAuthoritativeForm("Rectangle"); assertNull(terms); }