Spring JUnit Test and Rollback DB Transaction

In Spring, doing unit test with JUnit4 can be as simple as this:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration
public class HibernateDaoTest {
@Autowired
protected RepositoryHibernateDao repositoryHibernateDao;

@Test
@Transactional
public void submitProject() {
Project newp = new Project();
newp.setStatus("PENDING");
int pid = repositoryHibernateDao.save(newp);
assertTrue(pid > 0);
Project p = repositoryHibernateDao.getProjectDetail(pid);
assertEquals(p.getName(), name);
assertEquals(p.getSubmitUser(), owner);
repositoryHibernateDao.delete(p);
}
}

With the annotation @Transactional, when the test is finished, the database is supposed to roll back to the state before the test. But this does not happen in my Spring/Hibernate/MySQL setting.

It turns out to be that in order to support transaction, the MySQL table must be an InnoDB table.

Usually the tables are MyISAM ones, which are non-transactional. The MyISAM table provides high-speed storage and retrieval, as well as fulltext searching capabilities. It is supported in all MySQL configurations, and is the default storage engine unless you have configured MySQL to use a different one by default.

On the other hand, the InnoDB and BDB storage engines provide transaction-safe tables. InnoDB is included by default in all MySQL 5.0 binary distributions. Here describes how to
Convert a MyISAM table to innoDB. Basically, what needs to be done is: ALTER TABLE ... ENGINE=INNODB