Testing @Postconstruct with Mockito

Question

Why when I injecting mocks via Mockito my @Postconstruckt method is not calling?

@Service
public class MyService {
    public MyService() {
        System.out.println("CONSTRUKTOR");
    }

    @PostConstruct
    public void init() {
        System.out.println("POST CONSTRUCT");
    }

@RunWith(MockitoJUnitRunner.class)
public class Mockito1 {

    @InjectMocks
    private MyService service;

    @Before
    public void init() {
    }

Output: Only: CONSTRUKTOR

Solution 1

Because PostConstruct is only spring concept. But you can call postConstruct manually.

@Before
public void prepare() {
    MockitoAnnotations.initMocks(this);
    this.service.init(); //your Injected bean
}

Solution 2

I modified a little your service by adding a method foo:

@Service
public class MyService {
    public MyService() {
        System.out.println("CONSTRUKTOR");
    }

    @PostConstruct
    public void init() {
        System.out.println("POST CONSTRUCT");
    }

    public String foo() {
        return "bar";
    }
}

If you want to get behaviour, that you described, there are at least two possibilities:

1. @RunWith(SpringJUnit4ClassRunner.class) + @Autowired - that combination will let you to get a usual service in your test

   @RunWith(SpringJUnit4ClassRunner.class)
   @ContextConfiguration(classes = MyService.class)
   public class Mockito1 {
   
       @Autowired
       private MyService service;
   
       @Before
       public void init() {
       }
   
       @Test
       public void name() throws Exception {
           System.out.println(service.foo());
       }
   }
   

This code will print:

CONSTRUKTOR
POST CONSTRUCT
bar

2. @RunWith(SpringJUnit4ClassRunner.class) + @SpyBean - that combination will let you to get a service in your test and to modify it's behaviour using Mockito

   @RunWith(SpringJUnit4ClassRunner.class)
   @ContextConfiguration(classes = MyService.class)
   public class Mockito1 {
   
       @SpyBean
       private MyService service;
   
       @Before
       public void init() {
       }
   
       @Test
       public void name() throws Exception {
           System.out.println(service.foo());
           Mockito.when(service.foo()).thenReturn("FOO");
           System.out.println(service.foo());
       }
   }
   

This code will print:

CONSTRUKTOR
POST CONSTRUCT
bar
FOO

Comments

[M. Deinum]

@PostConstruct isn't only a spring concept, it isn't even a Spring annotation.