Unit testing EJBs with PowerMockito

I had to find a way to test a method from a stateful session bean (EJB PersonSABean implements PersonSF) defined in a service layer that calls another method from another stateful session bean (EJB HouseSFBean implements HouseSF) defined in a business layer.

To call that method from EJB HouseSFBean, the EJB PersonSABean needs to perform a lookup to get a reference to the EJB HouseSF. In that case, a static method is often created inside a static or final class. For instance :

public final class EjbUtil {
public static <T> T lookup(final Class<T> clazz) throws SomeException {
 InitialContext context = null;

try {
 context = new InitialContext(new PropertiesLoader().loadProperties("myProperties.txt"));
}
 return clazz.cast(context.lookup(name));
} catch (NamingException e) {
 throw new SomeException(e.getMessage());
} finally {
...
}

...

}

@TransactionManagement(TransactionManagementType.CONTAINER)
@Stateless(name = "PersonSA")
@Remote(value = { PersonSA.class })
@Interceptors(HandlerExceptionInterceptorSA.class)
public class PersonSABean extends BasicSABean implements PersonSA {
 ...
 private HouseSF houseSF;

 public HouseSF getHouseSF() {
    houseSF = EjbUtil.lookup(PersonSF.class, "ejb.company.project.application.HouseSF");
    return houseSF;
 }
}

But unit tests, unlike integration tests, are meant to test a specific method (or class). They are not meant to test the methods that it calls. So in my case, i do not need  to make – and should not make – a JNDI lookup to get a reference to the EJB HouseSF . So I have to mockup the EjbUtil.lookup(…)  static method.

Fortunately, PowerMockito can mock a static method so the solution is to use both Mockito and PowerMockito :

@RunWith(PowerMockRunner.class)
@PrepareForTest(EjbUtil.class)

import static org.mockito.Matchers.any;
import static org.mockito.Matchers.anyInt;
import static org.mockito.Matchers.anyListOf;
import static org.mockito.Matchers.anyString;
import static org.mockito.Mockito.stub;

import java.util.ArrayList;
import java.util.List;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.experimental.categories.Category;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.MockitoAnnotations;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

@Category(UnitTest.class)
@RunWith(PowerMockRunner.class)
@PrepareForTest(EjbUtil.class)
public class PersonSABeanTest {

@Mock
private HouseSF houseSF;

private PersonSABean personSABean;

@Before
public void setUp() throws Exception {
  MockitoAnnotations.initMocks(this);
  personSABean = new PersonSABean();
  personSABean.setHouseSF(houseSF);
  PowerMockito.mockStatic(EjbUtil.class);
}

@Test
public void testSomeMethod() throws SomeBusinessException {
  ...
  SomeDTO someDTO = new SomeDTO();
  stub(houseSF.someMethod(anyListOf(A.class), anyListOf(BDTO.class), any(CDTO.class), anyInt())).toReturn(someDTO);
  Mockito.when(EjbUtil.lookup(anyString(), Mockito.eq(HouseSF.class), anyString())).thenReturn(houseSF);
  ...
}

Link :
https://code.google.com/p/powermock/wiki/MockitoUsage13