Rollback transaction after @Test

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.

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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.