SpringBoot、JPA 和 Hibernate 实体层的单元测试

Question

I'm implementing a project using SpringBoot, JPA and Hibernate.

I implemented the DB entities layer with JPA repository.

I'm interested to understand the best practice to write unit-tests for this layer.

• Point number one: for this layer, from your point of view, it's necessary to use an integrated DB or it' necessary to mock using, for example, Mockito?
• My idea, for this layer, it's, for example, to test the entity structure: check fields validation for example, insert and retrieve some data. In this way, I think I could cover the tests for this entire data-layer.

I'm trying to understand these best practices and, in the mean time, I tried to write a first example of the test:

@ActiveProfiles("test")
@DisplayName("Test Item JPA Entity")
@DataJpaTest
@AutoConfigureTestDatabase( replace = AutoConfigureTestDatabase.Replace.NONE )
public class ItemEntityTest {

    @Autowired
    MyEntityRepository repo;

    @Test
    @Transactional
    public void testEntityCreation() {

        Entity e = new Entity();
        e.setMyField1("A");
        e.setMyField1("A");
        //e.setMandatoryField("C")

        repo.save(e);

    }
}

Unfortunately, In this case, I notiest that the fields validation is not applied (@NotNull or @NotEmpty, or @Column(nullable=false), etc... If I try to save the entity into my application the validation works fine... the exceptions are raised). Why?

Also some "automatic fields" (for example creation time and last modification time) are not filled.

Is this the correct path? Ho to test my entities definition?

Answer 1

As mentioned in that answer, the problem is that with @DataJpaTest spring will use TestEntityManager and the transactional annotation will override the default auto commit and rollback behaviour by spring boot.

So your test method will pass and assuming the hibernate is the ORM being used here, when the flushing will take place finally, hibernate's pre-insert event will fire and validations will be applied, but your test case will pass till then so it will produce false positive (as the terms used in spring docs)

Solution: You would need to inject entity manager in your test and flush manually it so that hibernate pre-insert event triggers before your test completes.

@ActiveProfiles("test")
@DisplayName("Test Item JPA Entity")
@DataJpaTest
@AutoConfigureTestDatabase( replace = AutoConfigureTestDatabase.Replace.NONE )
public class ItemEntityTest {

    @Autowired
    MyEntityRepository repo;

    @Autowired
    private TestEntityManager em;

    @Test
    @Transactional
    public void testEntityCreation() {

        Entity e = new Entity();
        e.setMyField1("A");
        e.setMyField1("A");
        //e.setMandatoryField("C")

        repo.save(e);
        
        em.flush();
    }
}

This must trigger your validations on the entity applied, this is documented in spring framework docs . Please notice that the documentation is about spring framework and uses session factory, but the concept is same

You may check the spring boot docs as well, which points to the spring framework docs for this behaviour.