Unit Life Cycle

I have a lifecycle issue running a test suite using JUnit.

To write convenient test tests JPA 2.0 As a Java developer I want:

• Initialize an EntityManagerFactory instance once before all test suites. I reach the object using @BeforeClass annotation
• Create an instance of EntityManager and start a new transaction before each test case and roll back the started transaction, such as AOP before / after or around the board.
• Be able to perform any installation / break operations before / after in any derived set of tests

I wrote a lot of JUnit tests. But in this case, I have problems with the second and third items from the list.

Please take a look at the following test suite examples:

Abstract test suite :

public abstract class AbstractPersistenceTest {

    protected static EntityManagerFactory emf;
    protected EntityManager em;

    @BeforeClass
    public static void setUpClass() {
        emf = Persistence.createEntityManagerFactory("test");
    }

    @Before
    public void setUp() {
        em = emf.createEntityManager();
        em.getTransaction().begin();
    }

    @After
    public void tearDown() {
        em.getTransaction().rollback();
        em.close();
    }

    @AfterClass
    public static void tearDownClass() {
        emf.close();
    }

}

:

public class EmployeeJpqlTest extends AbstractPersistenceTest {

    private Employee john;
    private Employee jack;

    @Before
    public void setUp() {
        john = new Employee("John Doe", 1000);
        jack = new Employee("Jack Line", 1010);

        em.persist(john);
        em.persist(jack);
    }

    @Test
    public void itShouldRetrieveAllEmplloyees() {
        TypedQuery<Employee> query = em.createQuery("SELECT e FROM Employee e",
                Employee.class);
        List<Employee> employees = query.getResultList();

        assertArrayEquals(new Employee[] { john, jack }, employees.toArray());
    }

    @Test
    public void itShoulRetrieveAllEmployeeNames() {
        TypedQuery<String> query = em.createQuery(
                "SELECT e.name FROM Employee e", String.class);
        List<String> names = query.getResultList();

        assertArrayEquals(new String[] { john.getName(), jack.getName() },
                names.toArray());
    }

}

- JUnit NullPointerException setUp() . .

start/rollbacking setUp()/tearDown() ? , , JUnit, ?

.