### Question:
MessengerServiceImpl implements MessengerService { @Override public List<Messenger> getMessenger(String sendId, String receiveId) { List<Messenger> messengers; messengers = em.createQuery("SELECT a FROM Messenger AS a" + " WHERE ((a." + stringSendId + " = :"+ stringSendId + " AND a.receiveId = :receiveId) OR (a." + stringSendId +" = :sendId2 AND a.receiveId = :receiveId2))" + " ORDER BY datetime ASC" , Messenger.class).setParameter(stringSendId, sendId).setParameter("receiveId", receiveId).setParameter("sendId2", receiveId).setParameter("receiveId2", sendId).getResultList(); return messengers; }  @Override List<Messenger> getAll(); @Override void addMessenger(Messenger messenger); @Override List<Messenger> getMessenger(String sendId, String receiveId); @Override int seenMessage(Messenger messenger); @Override List<Object> getInfo(String userId);  }### Answer:
@Test void getMessengerTest() { initDataStore2(); List<Messenger> messengers = Messengerserviceimpl.getMessenger("1234", "1235"); int size2 = messengers.size(); assertEquals(2,size2); }