Rollback transaction after @Test

First of all, I've found a lot of threads on StackOverflow about this, but none of them really helped me, so sorry to ask possibly duplicate question.

I'm running JUnit tests using spring-test, my code looks like this

@RunWith(SpringJUnit4ClassRunner.class)  
@ContextConfiguration(locations = {})
public class StudentSystemTest {

    @Autowired
    private StudentSystem studentSystem;

    @Before
    public void initTest() {
    // set up the database, create basic structure for testing
    }

    @Test
    public void test1() {
    }    
    ...  
}

My problem is that I want my tests to NOT influence other tests. So I'd like to create something like rollback for each test. I've searched a lot for this, but I've found nothing so far. I'm using Hibernate and MySql for this

Just add @Transactional annotation on top of your test:

@RunWith(SpringJUnit4ClassRunner.class)  
@ContextConfiguration(locations = {"testContext.xml"})
@Transactional
public class StudentSystemTest {

By default Spring will start a new transaction surrounding your test method and @Before/@After callbacks, rolling back at the end. It works by default, it's enough to have some transaction manager in the context.

From: 10.3.5.4 Transaction management (bold mine):

In the TestContext framework, transactions are managed by the TransactionalTestExecutionListener. Note that TransactionalTestExecutionListener is configured by default, even if you do not explicitly declare @TestExecutionListeners on your test class. To enable support for transactions, however, you must provide a PlatformTransactionManager bean in the application context loaded by @ContextConfiguration semantics. In addition, you must declare @Transactional either at the class or method level for your tests.

Aside: attempt to amend Tomasz Nurkiewicz's answer was rejected:

This edit does not make the post even a little bit easier to read, easier to find, more accurate or more accessible. Changes are either completely superfluous or actively harm readability.

Correct and permanent link to the relevant section of documentation about integration testing.

To enable support for transactions, you must configure a PlatformTransactionManager bean in the ApplicationContext that is loaded via @ContextConfiguration semantics.

@Configuration
@PropertySource("application.properties")
public class Persistence {
    @Autowired
    Environment env;

    @Bean
    DataSource dataSource() {
        return new DriverManagerDataSource(
                env.getProperty("datasource.url"),
                env.getProperty("datasource.user"),
                env.getProperty("datasource.password")
        );
    }

    @Bean
    PlatformTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dataSource());
    }
}

In addition, you must declare Spring’s @Transactional annotation either at the class or method level for your tests.

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {Persistence.class, SomeRepository.class})
@Transactional
public class SomeRepositoryTest { ... }

Annotating a test method with @Transactional causes the test to be run within a transaction that will, by default, be automatically rolled back after completion of the test. If a test class is annotated with @Transactional, each test method within that class hierarchy will be run within a transaction.

The answers mentioning adding @Transactional are correct, but for simplicity you could just have your test class extends AbstractTransactionalJUnit4SpringContextTests.