How do I reset my database state after each unit test without making the whole test a transaction?

Question

I'm using Spring 3.1.1.RELEASE, Hibernate 4.1.0.Final, JPA 2, JUnit 4.8.1, and HSQL 2.2.7. I want to run some JUnit tests on my service methods, and after each test, I would like any data written to the in-memory database to be rolled back. However, I do NOT want the entire test to be treated as a transaction. For example in this test

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({ "classpath:test-context.xml" })
public class ContractServiceTest 
{
    …

    @Autowired
    private ContractService m_contractService;

    @Test
    public void testUpdateContract()
    {
        // Add the contract
        m_contractService.save(m_contract);
        Assert.assertNotNull(m_contract.getId());
        // Update the activation date by 6 months.
        final Calendar activationDate = Calendar.getInstance();
        activationDate.setTime(activationDate.getTime());
        activationDate.add(Calendar.MONTH, 6);
        m_contract.setActivationDate(activationDate.getTime());
        m_contractService.save(m_contract);
        final List<Contract> foundContracts = m_contractService.findContractByOppId(m_contract.getOpportunityId());
        Assert.assertEquals(foundContracts.get(0), m_contract);
    }   // testUpdateContract

there are three calls to the service, ("m_contractService.save", "m_contractService.save", and "m_contractService.findContractByOppId") and each is treated as a transaction, which I want. But I don't know how to reset my in-memory database to its original state after each unit test.

Let me know if I need to provide additional information.

Answer 1

Since you are using hibernate, you could use the property hibernate.hbm2ddl.auto to create the database on startup every time. You would also need to force the spring context to be reloaded after each test. You can do this with the @DirtiesContext annotation.

This might add a bit extra overhead to your tests, so the other solution is to just manually delete the data from each table.