Entity is not deleted in a JUnit test with @Transactional

Question

I use @Transactional annotation on my JUnit tests sometimes. I use @Transactional in JUnit for Lazy fetching collections.

Currently I have faced with an unknown behavior for me of @Transactional annotation.

In my database I have one Car entity. I am deleting this entity in my test. If I use @Transactional on my test, then this entity IS NOT deleted from a database. Otherwise if I do not use @Transactional then the entity is deleted. I see this after every test in my database.

I have standard entity and repository. My entity:

@Entity 
public class Car {

    @Id
    @GeneratedValue
    private int id;

    private String model;

    //...constructors, getters and setters }

My repository:

public interface CarRepository extends JpaRepository<Car, Integer>{
    List<Car> findByModel(String mazda);
}

My test:

@RunWith(SpringRunner.class)
@SpringBootTest
public class RelationsTest {

    @Autowired
    CarRepository carRepository;

    @Test
    //@Transactional
    public void deleteCar() throws Exception {

        List<Car> cars = carRepository.findByModel("Mazda");
        assertThat(cars).hasSize(1);

        carRepository.deleteById(cars.get(0).getId());

    }

What is a reason that with @Transactional the entity is not deleted from a database?

Answer 1

From the Spring Boot documentation:

If your test is @Transactional, it rolls back the transaction at the end of each test method by default.