Mockito mock objects returns null

Question

I try to implement some tests for my JSF application and for the mocks I am using mockito. (I also use spring)

@RunWith(MockitoJUnitRunner.class) public class GeneralConfigServiceImplTest  {      private GeneralConfigService generalConfigService;      @Mock     private GeneralConfigDAO generalConfigDAO;      @Mock     private GeneralConfig gen;      @Before     public void setUp() {         MockitoAnnotations.initMocks(this);         generalConfigService = new GeneralConfigService();         ReflectionTestUtils.setField(generalConfigService, "generalConfigDAO", generalConfigDAO);                       }      @Test     public void testAddGeneralConfigCallDAOSuccess() throws DAOException, EntityNullException, IllegalEntityArgumentException, ParseException, EntityPersistException {         gen = createGeneralConfigs("label", "value");          generalConfigService.setInstance(gen);         generalConfigService.persist();         log.info(generalConfigService.getInstance().toString());     } } 

The test succeeds, but when I want to retrieve the instance with the getInstance method. All Parameters which I have set before (via the constructor before) are null. I am new to mocked objects, so is this behavior normal, or is there a mistake in my code?

Answer 1

It really depends on GeneralConfigService#getInstance() implementation. Also you can simplify your test code a lot if you use @InjectMocks annotation.

When using MockitoJUnitRunner you don't need to initialize mocks and inject your dependencies manually:

@RunWith(MockitoJUnitRunner.class) public class GeneralConfigServiceImplTest  {      @InjectMocks     private GeneralConfigService generalConfigService;      @Mock     private GeneralConfigDAO generalConfigDAO;      @Test     public void testAddGeneralConfigCallDAOSuccess() {        // generalConfigService is already instantiated and populated with dependencies here        ...     } } 

Answer 2

My problem here was the incorrect import for Test anotation:

Was

import org.junit.jupiter.api.Test;

Correct

import org.junit.Test;