### Question:
MachineResourceReferenceDaoImpl implements MachineResourceReferenceDao { @Override public com.google.code.morphia.Key<MachineResourceReference> createOrModify(MachineResourceReference machineResourceReference, WriteConcern writeConcern) { return datastore.save(machineResourceReference, writeConcern); } MachineResourceReferenceDaoImpl(Datastore datastore); @Override Long getCount(); @Override boolean create(MachineResourceReference machineResourceReference, WriteConcern writeConcern); @Override com.google.code.morphia.Key<MachineResourceReference> createOrModify(MachineResourceReference machineResourceReference, WriteConcern writeConcern); @Override Iterable<com.google.code.morphia.Key<MachineResourceReference>> createOrModify(Collection<MachineResourceReference> machineResourceReferences, WriteConcern writeConcern); @Override MachineResourceReference read(String id); @Override boolean update(MachineResourceReference machineResourceReference, WriteConcern writeConcern); @Override WriteResult delete(String id); @Override List<MachineResourceReference> getAllMachineResourceReferences(Page page);  }### Answer:
@Test public void testCreatOrModify_NullCollection() { assertFalse(machineResourceReferenceDao.createOrModify((Collection) null, WriteConcern.NONE).iterator() .hasNext()); }
@Test public void testCreatOrModify_EmptyCollection() { assertFalse(machineResourceReferenceDao.createOrModify((Collection) null, WriteConcern.NONE).iterator().hasNext()); }