EntityManager is null when unit testing with org.j

Question

Here is the unit testing code. When we run unit test code (SampleServiceTest2); EntityManager injected in AbstractDao is always null! How can we inject em during unit test.

*** SampleServiceTest2.java

import javax.inject.Inject;

import org.jglue.cdiunit.CdiRunner;
import org.junit.Test;
import org.junit.runner.RunWith;

@RunWith(CdiRunner.class)
public class SampleServiceTest2 {

    @Inject SampleService greeter; 

    @Test
    public void testGreeter() throws Exception { 
        System.out.println("before2");
        greeter.addSampleData(new SampleDataDto(), new KullaniciDto()); 
        System.out.println("after2");
    } 
}

*** SampleService.java

import javax.ejb.Stateless;
import javax.inject.Inject;
....

@Stateless
@SecuredBean
public class SampleService {

    @Inject 
    SampleLogic sampleLogic;

    @Yetki(tag="perm_add_sample_data")
    public void addSampleData(SampleDataDto data, KullaniciDto aktifKullaniciDto){
        SampleDataHelper sampleDataHelper = new SampleDataHelper();

        SampleData sampleData = sampleDataHelper.getEntity(data);
        KullaniciHelper kullaniciHelper = new KullaniciHelper();

        Kullanici kullanici = kullaniciHelper.getEntity(aktifKullaniciDto);
        sampleLogic.addData(sampleData, kullanici);
    }

}

**** SampleLogic.java

import javax.inject.Inject;

....

public class SampleLogic {
    @Inject 
    SampleDataDao sampleDataDao;

    public void addData(SampleData data, Kullanici kullanici) {
        addData1(data,kullanici);   
        System.out.println("SampleLogic : addData() called!");
    }

    public void addData1(SampleData data, Kullanici kullanici) {
        sampleDataDao.create(data, kullanici);
    }
}

**** SampleDataDao.java

public class SampleDataDao extends AbstractDao<SampleData> {
    private static final long serialVersionUID = 1L;
}

**** AbstractDao.java

public abstract class AbstractDao<T extends BaseEntity> implements Serializable {

    private static final long serialVersionUID = 1L;

    @PersistenceContext(unitName="meopdb")
    private EntityManager em;

    protected EntityManager getEm() {
        return em;
    }

    @SuppressWarnings("rawtypes")
    private Class entityClass;


    @SuppressWarnings("rawtypes")
    private Class getEntityClass() {
        if (entityClass == null) {
            entityClass = (Class) ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[0];
        }
        return entityClass;
    }

    public T create(T t, Kullanici kullanici) {
        if (t.getId() != null) {
            throw new IllegalStateException("Create Operation: Oid should be null");
        }
        t.setId(getSeqNextValue(t));
        t.setEklemeZamani(new Timestamp(Calendar.getInstance().getTimeInMillis()));
        t.setEkleyenKullaniciId(kullanici.getId());

        t.setDurumId(EnumDurum.AKTIF.getValue());

        t = em.merge(t);
        em.flush();
        return t;
    }
}

Answer 1

If you test with CDIUnit, the only thing you get is CDI injections, not the full power of Java EE. Injecting entityManager using @PersistenceContext into AbstractDAO is not part of standalone CDI, it is only supported when application is running within a Java EE application server.

The solution is to inject EntityManager using CDI mechanism and create a producer. The producer could be then switched for an alternative in unit tests to provide test entityManager. However, setting up JPA in a standalone unit test is not so straightforward, as you need to specify connection properties directly in persistence.xml file. Also, do not forget to add dependencies on a JPA implementation (hibernate, eclipselink) into your test dependencies.

However, if you do not want to adapt your application's code or you need more than CDI in your tests, you should have a look at Arquillian Java EE test framework.

Here is an example for CDIUnit:

public abstract class AbstractDao<T extends BaseEntity> implements Serializable {
...
    @Inject
    @Named("meopdb")
    private EntityManager em;
...
}

// producer in application - just a wraper over `@PersisteneContext`
public class EntityManagerProducer {
    @Produces
    @PersistenceContext(unitName="meopdb")
    @Named("meopdb")
    private EntityManager em;
}

/* producer in your test sources - it creates entityManager via API calls instead of injecting via `@PersistenceContext`. Also, a different persistence unit is used so that it does not clash with main persistence unit, which requires datasource from app server 
*/
public TestEntityManagerProducer {
    @Produces
    @ProducesAlternative // CDIUnit annotation to turn this on as an alternative automatically
    @Named("meopdb")
    public EntityManager getEm() {
        return Persistence
                .createEntityManagerFactory("meopdb-test")
                .createEntityManager();
    }

}

And it is not yet enough. You need to create a new persistence.xml in your test resources with the test persistence unit named "meopdb-test". For this unit you need to specify RESOURCE_LOCAL transaction-type, and specify connection information. And last thing not to forget - you need to list all your entities in the persistence.xml, or in external orm file. This is because your tests run outside of application server. Inside app server, JPA can find entities automatically.