### Question:
SourceDocumentReferenceDaoImpl implements SourceDocumentReferenceDao { @Override public Iterable<com.google.code.morphia.Key<SourceDocumentReference>> createOrModify(Collection<SourceDocumentReference> sourceDocumentReferences, WriteConcern writeConcern) { if (null == sourceDocumentReferences || sourceDocumentReferences.isEmpty()) { return Collections.EMPTY_LIST; } return datastore.save(sourceDocumentReferences, writeConcern); } SourceDocumentReferenceDaoImpl(Datastore datastore); @Override Long getCount(); @Override boolean create(SourceDocumentReference sourceDocumentReference, WriteConcern writeConcern); @Override Iterable<com.google.code.morphia.Key<SourceDocumentReference>> createOrModify(Collection<SourceDocumentReference> sourceDocumentReferences, WriteConcern writeConcern); @Override void createOrModify(SourceDocumentReference sourceDocumentReference, WriteConcern writeConcern); @Override SourceDocumentReference read(String id); @Override List<SourceDocumentReference> read(List<String> ids); @Override boolean update(SourceDocumentReference sourceDocumentReference, WriteConcern writeConcern); @Override WriteResult delete(String id); @Override List<SourceDocumentReference> findByRecordID(String recordID); @Override List<SourceDocumentReference> deactivateDocuments(ReferenceOwner owner, WriteConcern concern);  }### Answer:
@Test public void test_CreateOrModify_NullCollection() throws Exception { assertFalse(sourceDocumentReferenceDao.createOrModify((Collection) null, WriteConcern.NONE).iterator().hasNext()); }
@Test public void test_CreateOrModify_EmptyCollection() throws Exception { assertFalse(sourceDocumentReferenceDao.createOrModify(Collections.EMPTY_LIST, WriteConcern.NONE).iterator().hasNext()); }
@Test public void testCreateOrModify() throws Exception { final SourceDocumentReference sourceDocumentReference = new SourceDocumentReference(new ReferenceOwner("1", "1", "1"), "test", null, null, 0l, null, true); assertNull(sourceDocumentReferenceDao.read(sourceDocumentReference.getId())); sourceDocumentReferenceDao.createOrModify(sourceDocumentReference, WriteConcern.NONE); assertNotNull(sourceDocumentReferenceDao.read(sourceDocumentReference.getId())); assertEquals(sourceDocumentReferenceDao.read(sourceDocumentReference.getId()).getUrl(), sourceDocumentReference.getUrl()); final SourceDocumentReference updatedSourceDocumentReference = new SourceDocumentReference(sourceDocumentReference.getId(), new ReferenceOwner("1", "1", "1"), "test2", null, null, 0l, null, true); sourceDocumentReferenceDao.createOrModify(updatedSourceDocumentReference, WriteConcern.NONE); assertEquals(sourceDocumentReferenceDao.read(sourceDocumentReference.getId()).getUrl(), updatedSourceDocumentReference.getUrl()); assertNotEquals(sourceDocumentReferenceDao.read(sourceDocumentReference.getId()).getUrl(), sourceDocumentReference.getUrl()); sourceDocumentReferenceDao.delete(sourceDocumentReference.getId()); }