How to use should_serialization_work method of org.mockitousage.basicapi.MocksSerializationForAnnotationTest class

Even more meaningful :

import static org.mockito.Mockito.never;
import static org.mockito.Mockito.verify;

// ...

verify(dependency, never()).someMethod();

The documentation of this feature is there §4 "Verifying exact number of invocations / at least x / never", and the never javadoc is here.

For the service, it's good practice to either inject through the constructor or setter. This makes it easy to mock and pass in during unit testing. As for the mocking, you should use a framework like Mockito. Then you can do stuff like

MyService service = Mockito.mock(MyService.class);
when(service.getObject()).thenReturn(new Object());

HttpHeaders headers = Mockito.mock(HttpHeaders.class);
when(headers.getHeaderString("X-Header")).thenReturn("blah");

UriInfo uriInfo = Mockito.mock(UriInfo.class);
when(uriInfo.getRequestUri()).thenReturn(URI.create("http://localhost"));

Then you can just pass all these mocks to your resource class when UNIT testing.

For INTEGRATION testing you won't need to mock the headers or uriinfo. The actual ones will get passed in. But you can still mock the service if you want. Here's an example

public class MockServiceTest extends JerseyTest  {

    public static interface Service {
        String getMessage(String name);
    }

    @Path("message")
    public static class MessageResource {

        private final Service service;

        public MessageResource(Service service) {
            this.service = service;
        }

        @GET
        public String get(@QueryParam("name") String name,
                          @Context HttpHeaders headers,
                          @Context UriInfo uriInfo) {
            String nameQuery = uriInfo.getQueryParameters().getFirst("name");
            String header = headers.getHeaderString("X-Header");
            assertNotNull(nameQuery);
            assertNotNull(header);
            return service.getMessage(name);
        }
    }

    private Service service;

    @Override
    public ResourceConfig configure() {
        service = Mockito.mock(Service.class);
        return new ResourceConfig().register(new MessageResource(service));
    }

    @Test
    public void testIt() {
        Mockito.when(service.getMessage("peeskillet")).thenReturn("Hello peeskillet");

        Response response = target("message").queryParam("name", "peeskillet").request()
                .header("X-Header", "blah")
                .get();
        assertEquals(200, response.getStatus());
        assertEquals("Hello peeskillet", response.readEntity(String.class));
    }
}

You need create real A class because you want to test it but you need to mock other classes used in A class. Also, you can find mockito documentation says that don't mock everything.

class ATest {
        @Mock
        private B b;
        private A a;
        @Before
        public void init() {
            MockitoAnnotations.initMocks(this);
            a = new A(b);
        }
        @Test
        public String someMethodTest() {
            String result = "result";
            Mockito.when(b.execute()).thenReturn(result);
            String response = a.someMethod();
            Mockito.verify(b,  Mockito.atLeastOnce()).execute();
            assertEquals(response, result);
        }
    }

@Mock creates a mock. @InjectMocks creates an instance of the class and injects the mocks that are created with the @Mock (or @Spy) annotations into this instance.

Note you must use @RunWith(MockitoJUnitRunner.class) or Mockito.initMocks(this) to initialize these mocks and inject them (JUnit 4).

With JUnit 5, you must use @ExtendWith(MockitoExtension.class).

@RunWith(MockitoJUnitRunner.class) // JUnit 4
// @ExtendWith(MockitoExtension.class) for JUnit 5
public class SomeManagerTest {

    @InjectMocks
    private SomeManager someManager;

    @Mock
    private SomeDependency someDependency; // this will be injected into someManager
 
     // tests...

}

According to the Mockito documentation you can set different behavior for consecutive method calls.

when(mock.someMethod("some arg"))
    .thenThrow(new RuntimeException())
    .thenReturn("foo");

In case of a void method you can do something similar (Mockito documentation)

doThrow(new RuntimeException())
    .doNothing()
    .when(mock).doSomething();

Check the Java API for List.
The get(int index) method is declared to throw only the IndexOutOfBoundException which extends RuntimeException.
You are trying to tell Mockito to throw an exception SomeException() that is not valid to be thrown by that particular method call.

To clarify further.
The List interface does not provide for a checked Exception to be thrown from the get(int index) method and that is why Mockito is failing.
When you create the mocked List, Mockito will use the definition of List.class to creates its mock.

The behavior you are specifying with the when(list.get(0)).thenThrow(new SomeException()) doesn't match the method signature in List API, because get(int index) method does not throw SomeException() so Mockito fails.

If you really want to do this, then have Mockito throw a new RuntimeException() or even better throw a new ArrayIndexOutOfBoundsException() since the API specifies that that is the only valid Exception to be thrown.

Question might be a bit old but I will put an answer in case someone stumbles across.

• I'm using Mockito and JUnit.
• AccountRepository is a plain spring data repository extending JPARepository.
• Account is a plain JPA entity.

To test your services and mock Spring Data repositories, you need something like below.

package foo.bar.service.impl;

import foo.bar.data.entity.Account;
import foo.bar.data.repository.AccountRepository;
import foo.bar.service.AccountService;

import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.runners.MockitoJUnitRunner;

@RunWith(MockitoJUnitRunner.class)
public class AccountServiceImplTest {

    @Mock
    private static AccountRepository accountRepository;

    @InjectMocks
    private static AccountService accountService = new AccountServiceImpl();

    private Account account;

    @Test
    public void testFindAccount() {

        Integer accountId = new Integer(1);

        account = new Account();
        account.setId(accountId);
        account.setName("Account name");
        account.setCode("Accont code");
        account.setDescription("Account description");

        Mockito.when(accountRepository.findOne(accountId)).thenReturn(account);

        Account retrivedAccount = accountService.findAccount(accountId);

        Assert.assertEquals(account, retrivedAccount);

    }

}

Just point that with Mockito you can also use AdditionalMatchers and ArgumentMatchers

import static org.mockito.AdditionalMatchers.not;
import static org.mockito.ArgumentMatchers.eq;

//anything but not "ejb"    
mock.someMethod(not(eq("ejb")));

According its documentation:

Example of using logical and(), not(), or() matchers:

//anything but not "ejb"
mock.someMethod(not(eq("ejb")));

There is more info in this other SO question

Hope it helps

I think the reason may be that mock object libraries typically create mocks by dynamically creating classes at runtime (using cglib). This means they either implement an interface at runtime (that's what EasyMock does if I'm not mistaken), or they inherit from the class to mock (that's what Mockito does if I'm not mistaken). Both approaches do not work for static members, since you can't override them using inheritance.

The only way to mock statics is to modify a class' byte code at runtime, which I suppose is a little more involved than inheritance.

That's my guess at it, for what it's worth...