How to cleanup h2 db after each junit test?

Question

I am making junit tests which adds some users before each test case. The code is:

@BeforeEach
    void setUp() {
        saveUser();
        saveEntry();
    }
    
    @Test
    void saveUser() {
        User user = new User();
        user.setUserId(null);
        user.setUsername("John");
        user.setEmail("john@foo.com");
        user.setPassword("password");
        userService.saveUser(user);
    }

    @Test
    void saveEntry() {
        Entry entry = new Entry();
        entry.setText("test text");
        entry.setUserId(1L);
        entryService.saveEntry(entry);
    }

As you see I am using the methods that I have in my service layer to create entries and users. If I run the tests one by one there is no problem. But when I run all tests then db is not returning 1 item and returning multiple items so exception occurs.

I need to cleanup h2 db after each test with maybe @AfterEach annotation but I do not have and delete method in my code to invoke. How can I cleanup the H2 db ?

Answer 1

In addition to @J Asgarov answer which is correct providing you use spring-boot if you want to perform some actions before and after each test (more specifically before @Before and after @After methods) you can use @Sql annotation to execute specific sql script for example from test resources.

@Sql("init.sql")
@Sql(scripts = "clean.sql", executionPhase = Sql.ExecutionPhase.AFTER_TEST_METHOD)
public class TestClass
}

It might be handy for sequences, since they don't care of rollback.

Regarding @Transactional mentioned by @Mark Bramnik be careful, because the transaction spans for entire test method, so you cannot verify correctness of the transaction boundaries.