Spring Boot - Unit Testing ApplicationReadyEvent business logic

Question

I have a simple service where I prepopulate a user db table with a default user. The service looks like this:

@Service
public class BootstrapService
{
    @Autowired
    UserRepository userRepository;

    public void bootstrap()
    {
        User user = new User("admin", "password");
        userRepository.save(user);
    }
}

I call this service on application startup by using an ApplicationListener:

@Component
public class ApplicationStartup implements ApplicationListener<ApplicationReadyEvent>
{
    @Autowired
    private BootstrapService bootstrapService;

    @Override
    public void onApplicationEvent(final ApplicationReadyEvent event)
    {
        bootstrapService.bootstrap();
    }
}

Now I want to write a unit test for the BootstrapService that checks if a user was really added, like this:

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = MyApplication.class)
@Transactional
public class BootstrapServiceTests
{
    @Autowired
    private UserRepository userRepository;

    @Autowired
    private BootstrapService bootstrapService;

    @Test
    public void testBootstrap()
    {
        bootstrapService.bootstrap();

        assertEquals(1, userRepository.count());
    }
}

However what happens is that the bootstrapService.bootstrap() function gets called twice - once by the ApplicationListener and once by the test itself, resulting in two users being added to the DB.

How can I prevent the ApplicationListener#ApplicationReadyEvent getting triggered while running the test?

Answer 1

As mentioned in comment, You can try to mock the listener (but I'm not sure if it will work in this precise case). Other way that I can think of (this works for sure) is to use Spring profiles, to exclude ApplicationStartup from running in test profile, like this:

@Component
@Profile("!test")
public class ApplicationStartup implements ApplicationListener<ApplicationReadyEvent>

Then when You run Your tests, simply use environment switch: --spring.profiles.active=test

The drawback is that ApplicationStartup will be excluded from every test run with "test" profile.