TestNG + Spring 2.5

First of all, you need a dataSource bean at your applicationContext.xml:

Write a class that allows you to test database code (test your DAO's, mappings or your persistence layer methods). Transaction is rolled back at the end of test method.

public class SimpleTest extends AbstractTransactionalTestNGSpringContextTests
public void test()
// applicationContext is injected and using contactDAO
// you can save Contact objects to DB in a database transaction
ContactDAO contactDAO = applicationContext.getBean("contactDAO");
contactDAO.save(new Contact());

List contacts = contactDAO.findAll();
assert CollectionsUtils.isNotEmpty(contacts);

Read Appendix B of Sping in Action, 2nd Edition, Manning for more details (perharps you need to commit test changes, find out how to do it there...).