Spring Test Junit throws null pointer exception

Question

I have this code for testing :

private static final Integer documentSetId = 1143;
private static final Integer dsLifeCycleStateId = 1;
private static final String dsLifecycleState = "CVS_CREATED";

CVBusiness cvBusinessTest;


DocumentService documentService;

DocumentSetRepository documentSetRepository;

private DocumentSet documentSet;

private DSLifeCycleState dsLifeCycleState;

@Before
public void setUp(){
    cvBusinessTest = new CVBusinessImpl();
    documentService = mock(DocumentService.class);  
    documentSetRepository = mock(DocumentSetRepository.class);

    documentSet = new DocumentSet();
    dsLifeCycleState = new DSLifeCycleState();

    documentSet.setActive(true);
    documentSet.setDocumentSetId(documentSetId);
    documentSet.setMarkedForTranslation(false);

    dsLifeCycleState.setDsLifeCycleStateId(dsLifeCycleStateId);
    dsLifeCycleState.setLabel(dsLifecycleState);

    documentSet.setDsLifeCycleState(dsLifeCycleState);

    when(documentService.getDocumentSetById(documentSetId)).thenReturn(documentSet);
    when(documentService.updateDocumentSet(documentSet)).thenReturn(documentSet);
    when(documentSetRepository.findOne(documentSetId)).thenReturn(documentSet);
}

@Test
public void markedForTranslationTest() {

    boolean retValue = true;

    DocumentSet docSet = documentService.getDocumentSetById(documentSetId);
    dsLifeCycleState = docSet.getDsLifeCycleState();

    if (dsLifeCycleState.getLabel().equals(LifeCycleStateEnum.CVS_CREATED.message()) && docSet.isActive() && !docSet.isMarkedForTranslation() && ((docSet.getfDR() == null) || docSet.getfDR().equals(""))){
        documentSet.setMarkedForTranslation(true);
        retValue = documentService.updateDocumentSet(documentSet) != null;
    }

   // retValue = cvBusinessTest.markedForTranslation(documentSetId);

    assertTrue(retValue); 

}

and when i run Junit, it finished with errors: java.lang null pointer exception.

Which error points the method bellow

DocumentSet documentSet = documentService.getDocumentSetById(id)

which is in CVBusiness package extended by CVBusinessImpl.

My question is why documentService in CVBusinessImpl throws Null exception? Thanks!

Answer 1

Maybe you missed to use Spring in your Test? How the documentService is injected?

Add @RunWith(SpringJUnit4ClassRunner.class) to your test class to enable Spring in the test. If you use autowire that should be all. You may also need a @ContextConfiguration annotation to your test and/or add @Resource to the members to be injected.

Answer 2

In your setup, you create your class to test:

cvBusinessTest = new CVBusinessImpl();

and one of the services it requires:

documentService = mock(DocumentService.class);  

but you never wire them together. So when your CVBusinessImpl implementation calls:

DocumentSet documentSet = documentService.getDocumentSetById(id)

documentService is still null.

You should wire your objects before testing, either through using a Spring test runner or through setting that field. Something in your setup method like:

cvBusinessTest.setDocumentService(documentService);