Spring @Transactional method doesn't rollback

I've got a question to Spring, hibernate and testng.

I am developing an app and try to write a transactional unit test. The question is how could I rollback my database operation when my buissnes method is marked as "transactional"?

The code:

@Test
@ContextConfiguration(locations = { "classpath:applicationContext.xml" })
@TransactionConfiguration(defaultRollback = true)
public class SampleTest extends
AbstractTransactionalTestNGSpringContextTests {


@Autowired
private AuthorDao authorDao; 

@BeforeTest
void createAppCtx() {
    ApplicationContext applicationContext = new ClassPathXmlApplicationContext(
            "/applicationContext.xml");

}


@Test
void testStg() {

    Person person = new Author();
    person.setFirstName("Edward");
    person.setLastName("Kowalski");
    authorDao.createAuthor(person);
}

In my authorDao I've following method:

@PersistenceContext
private EntityManager entityManager;

@Transactional
public Author createAuthor(Person author) {
    entityManager.persist(author);
    return (Author) author;
}

If the application context is needed, I can also attach it.

So as you can see the buisness method is transactional so there is a commit after calling. So point is how to avoid commit in the test class? Is it possible?

Many thanks for help.