集成测试中的测试条件和异常？

Question

I have written several Unit Tests and now switched to write Integration Test in our Java (Spring Boot) app. We use JUnit and Mockito libraries for testing.

As far as I know, Integration Tests check the entire rings rather than a function. However, I am confused that if I should also check the if conditions in the methods while integration testing. Here is an example service method:

@Override
public CountryDTO create(CountryRequest request) {

    if (countryRepository.existsByCodeIgnoreCase(countryCode)) {
        throw new EntityAlreadyExistsException();
    }

    final Country country = new Country();
    country.setCode("UK");
    country.setName("United Kingdom");

    final Country created = countryRepository.save(country);
    return new CountryDTO(created);
}

My questions are:

1. Can I write integration test for a Service or a Repository class?

2. when I test create method in my service above, I think I just create the proper request values ( CountryRequest ) in my Test class, then pass them to this create method and then check the returned value. Is that true? Or do I also need to test the condition in the if clause ( countryRepository.existsByCodeIgnoreCase(countryCode) )?

3. When I test find methods, I think I should first create record by calling create method and the proper place for this is @BeforeEach setup() {} method. Is that true?

Answer 1

1. If you wrote Unit tests that made sure, your services and repositories are working correctly (for example by validation and parameterized tests) I believe, you don't have to write integration tests for them. You should write integration tests to check the behavior of your app. By testing if your controller is working correctly you will also check if service and repo are ok.
2. I believe unit test should check it.
3. Do you ask if you should create record in db? If you want to test if repository is correctly communicating with service and it with controller, you have to do it with some data.