#46 implement support for nested tests in JUnit 5

[ArneLimburg]

No description provided.

[dadrus]

Hi @ArneLimburg. Thank you for the MR. I'm glad to accept it if you add an integration test showing the functionality.

[ArneLimburg]

Providing an implementation test to your code base is not that easy, because everything (even the JUnit 5 integration) is tested with JUnit 4.
Which approach should I take to write the integration test?
Shall I provide a new subproject? Or change the JUnit version of the JUnit 5 extension to JUnit 5 and provide a test then?

[dadrus]

I thought about something like (to b come part of jpa-unit-jpa2.1-hibernate-integration-test):

@ExtendWith(JpaUnit.class)
public class NestedJunit5Test {
    @PersistenceContext(unitName = "my-test-unit")
    private EntityManager entityManager;

    @Nested
    @DisplayName("Given an empty test table")
    class GivenAnEmptyTestTable {

        @Test
        @DisplayName("Then the size sould be zero")
        void thenTheSizeShouldBeZero() {
            final List<Depositor> list = entityManager
                    .createQuery("select d from Depositor d", Depositor.class)
                    .getResultList();
            assertEquals(list.size(), 0);
        }

        @Nested
        @DisplayName("When a row is inserted")
        class WhenARowIsInserted {

            @BeforeEach
            @Transactional(TransactionMode.COMMIT)
            void setUp() {
                final Depositor depositor = new Depositor("Max", "Doe");
                entityManager.persist(depositor);
            }

            @Test
            @DisplayName("Then the size should be one")
            void thenTheSizeShouldBeOne() {
                final List<Depositor> list = entityManager
                        .createQuery("select d from Depositor d", Depositor.class)
                        .getResultList();
                assertEquals(list.size(), 0);
            }
        }
    }
}

[dadrus]

Providing an implementation test to your code base is not that easy, because everything (even the JUnit 5 integration) is tested with JUnit 4.

I know. When first JUnit5 integration was implemented, JUnit5 was not released. It was still Beta I think. Updating of all these tests and a couple of other improvements/simplifications is still in my TODO list even the project doesn't look like it is maintained

[dadrus]

If you wonder why I paste a code here and not do it my myself, I've already created a local branch half a year ago where I just added the tests without any implementation to support that. Due to lack of time I didn't work on that. I'll push it, so you can see whether your implementation does provide the support I thought about.

[dadrus]

Here is the branch: https://github.com/dadrus/jpa-unit/tree/junt5_nested_test_support

[ArneLimburg]

I'll take a look at it

[dadrus]

please pull again. I've forgotten to commit the changes.

[ArneLimburg]

OK, the nested test works, but there seems to be a problem with datasets or transaction. I'll take a look into it later.

[ArneLimburg]

JUnit 5 introduces a new lifecycle callback "postProcessTestInstance", which does not really match the old jpa-unit code. My patch matches all to DecoratorExecutor#processBefore, which will potentially lead to multiple injections of the same EntityManager in nested situations.
To fix this, a deeper refactoring is necessary that introduces such method in DecoratorExecutor and somehow handles the old cases.