Mocking raw String in unit testing for Spring Boot service layer

Question

I am trying to write unit tests for a service layer method finding Player s by name. The method calls a JPA repository method and returns a Page object. I want the test to verify that the correct method from repository was indeed called.

The test class

@RunWith(SpringRunner.class)
@SpringBootTest(classes = {PlayerService.class})
public class PlayerServiceTest {

    @Autowired
    PlayerService playerService;

    @MockBean
    PlayerRepository playerRepository;


    @Test
    public void whenListPlayersByName_thenShouldCallFindMethodWithPageableArgAndNameArg(){
        Pageable pageableStub = Mockito.mock(Pageable.class);
        String name = "xxx";
        Mockito.when(playerRepository.findByNameContainingIgnoreCase(any(String.class), any(Pageable.class)))
                .thenReturn(any(Page.class));

        //1st attempt:
        //playerService.listPlayersByName(name, pageableStub);
        playerService.listPlayersByName(eq(name), pageableStub);

        verify(playerRepository).findByNameContainingIgnoreCase(any(String.class), any(Pageable.class));
    }

My problem

The test fails with a message:

org.mockito.exceptions.misusing.InvalidUseOfMatchersException: 
Invalid use of argument matchers!
2 matchers expected, 1 recorded:
-> at com.domin0x.player.PlayerServiceTest.whenListPlayersByName_thenShouldCallFindMethodWithPageableArgAndNameArg(PlayerServiceTest.java:60)

This exception may occur if matchers are combined with raw values:
    //incorrect:
    someMethod(anyObject(), "raw String");
When using matchers, all arguments have to be provided by matchers.
For example:
    //correct:
    someMethod(anyObject(), eq("String by matcher"));

Following the advice I changed the name to eq(name) but that results in a different issue:

Argument(s) are different! Wanted:
com.domin0x.player.PlayerRepository#0 bean.findByNameContainingIgnoreCase(
    <any java.lang.String>, <any org.springframework.data.domain.Pageable>);

Actual invocation has different arguments:
com.domin0x.player.PlayerRepository#0 bean.findByNameContainingIgnoreCase(
null,     Mock for Pageable, hashCode: 309271464
;

Any advice what should I change in the test?

The service class

@Service
public class PlayerService {
    public Page<Player> listPlayersByName(String name, Pageable pageable) {
        return repository.findByNameContainingIgnoreCase(name, pageable);
    }

The repository interface

@Repository
public interface PlayerRepository extends JpaRepository<Player, Integer> {

    Page<Player> findByNameContainingIgnoreCase(String name, Pageable pageable);
}

Answer 1

It took me a while to figure this one out.

in thenReturn , you are calling any(Page.class) . Instead, you should return either an actual Page object, or a mock Page object).

It's also better to avoid using "any" unless you have no way to know the identity.

Page<Player> pageStub = (Page<Player>)Mockito.mock(Page.class);
Mockito.when(playerRepository.findByNameContainingIgnoreCase(name, pageableStub))
            .thenReturn(pageStub);

Page<PlayerStub> result = playerService.listPlayersByName(name, pageableStub);

assertSame(pageStub, result);

// No need to call verify, since it couldn't get pageStub without calling the correctly stubbed method.

To clarify: eq() , any() , and other "matchers" should only be used as arguments to methods in when and verify . They should never be passed to the test subject, nor returned from any mocked object.