我无法将Mockito单元测试重写为Spock规范

Question

I have an implementation of Spring interface UserDetailsService :

@Service
public class UserDetailsServiceImpl implements UserDetailsService {

    private final UserRepository userRepository;

    @Autowired
    public UserDetailsServiceImpl(UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        final UserEntity user = userRepository.findByUsername(username);

        if (user == null) {
            throw new UsernameNotFoundException("Cannot find user with username " + username);
        }

        return new User(user);
    }
}

UserRepository is a standard interface extendng JpaRepository<UserEntity, Long> where UserEntity is my model class.

User is an implementation of UserDetails from Spring Framework.

And I wrote an unit test for this method using JUnit and Mockito. These tests are working:

@RunWith(SpringRunner.class)
@DirtiesContext
public class UserDetailsServiceTest {

    @Autowired
    private UserDetailsService userDetailsService;

    @Test
    public void shouldFindUser() throws Exception {
        // given
        final UserEntity user = new UserEntity(
                1L,
                "username",
                "username@email.com",
                "password",
                new ArrayList<>() // list of roles
        );

        when(UserDetailsServiceTestContext.userRepository.findByUsername(user.getUsername()))
                .thenReturn(user);

        // when
        final UserDetails result = userDetailsService.loadUserByUsername(user.getUsername());

        // then
        assertThat(result).isEqualTo(UserFactory.create(user));
        verify(UserDetailsServiceTestContext.userRepository)
                .findByUsername(user.getUsername());
    }

    @Test(expected = UsernameNotFoundException.class)
    public void shouldNotFindUser() throws Exception {
        // given
        when(UserDetailsServiceTestContext.userRepository.findByUsername(anyString()))
                .thenReturn(null);

        // when
        final UserDetails result = userDetailsService.loadUserByUsername(new String());
    }

    @TestConfiguration
    static class UserDetailsServiceTestContext {

        @MockBean
        private static UserRepository userRepository;

        @Bean
        UserDetailsService userDetailsService() {
            return new UserDetailsServiceImpl(userRepository);
        }
    }

}

And now I try to write these tests using Groovy and Spock framework. I wrote the following specification:

def 'should find user'() {
        given:
            def user = new UserEntity(
                1L,
                "username",
                "username@email.com",
                "password"
                new ArrayList<>() // list of roles
            )

            userRepository.findByUsername(user.username) >> user
            // userRepository.findByUsername(_ as String) >> user // also working

        when:
            def result = userDetailsService.loadUserByUsername(user.username)

        then:
            result == new User(user)
    }

and this test is working. But when I want verify calling of userRepository by add in section then: a statement 1 * userRepository.findByUsername(user.username) or 1 * userRepository.findByUsername(_ as String) I get an error UserDetailsServiceSpec.should find user and return new User:36 » UsernameNotFound . line 36 is in section when:

Answer 1

You need to do the stubbing and verification in one step

then:
1 * userRepository.findByUsername(user.username) >> user

For details here is my answer from Predefined mock response in Spock :

Please refer to the documentation

When mocking and stubbing the same method call, they have to happen in the same interaction. In particular, the following Mockito-style splitting of stubbing and mocking into two separate statements will not work:

setup:
subscriber.receive("message1") >> "ok"

when:
publisher.send("message1")

then:
1 * subscriber.receive("message1")

As explained in Where to Declare Interactions, the receive call will first get matched against the interaction in the then: block. Since that interaction doesn't specify a response, the default value for the method's return type (null in this case) will be returned. (This is just another facet of Spock's lenient approach to mocking.). Hence, the interaction in the setup: block will never get a chance to match.

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When dealing with spring and transaction proxies you might also run into this problem https://github.com/spockframework/spock/issues/758