### Question:
MachineResourceReferenceDaoImpl implements MachineResourceReferenceDao { @Override public boolean create(MachineResourceReference machineResourceReference, WriteConcern writeConcern) { if(read(machineResourceReference.getId()) == null) { datastore.save(machineResourceReference, writeConcern); return true; } else { return false; } } 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 testCreate() throws Exception { final MachineResourceReference processingLimits = new MachineResourceReference("1"); assertNotNull(processingLimits.getId()); machineResourceReferenceDao.create(processingLimits, WriteConcern.NONE); machineResourceReferenceDao.delete(processingLimits.getId()); }