h2

bron: Baeldung

When having project with MySQL db you can run your tests easily with an in memory database.

in pom.xml

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>6.0.6</version>
</dependency>
<dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-jpa</artifactId>
    <version>3.1.0</version>
</dependency>
<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <version>2.1.214</version>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>6.5.2.Final</version>
</dependency>

@Entity
public class Student {

    @Id
    private long id;

    private String name;

    // standard constructor, getters, setters
}

public interface StudentRepository extends JpaRepository<Student, Long> {
}

@Configuration
@EnableJpaRepositories(basePackages = "com.baeldung.persistence.dao")
@PropertySource("persistence-student.properties")
@EnableTransactionManagement
public class StudentJpaConfig {

    @Autowired
    private Environment env;

    @Bean
    public DataSource dataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName(env.getProperty("jdbc.driverClassName"));
        dataSource.setUrl(env.getProperty("jdbc.url"));
        dataSource.setUsername(env.getProperty("jdbc.user"));
        dataSource.setPassword(env.getProperty("jdbc.pass"));

        return dataSource;
    }

    // configure entityManagerFactory

    // configure transactionManager

    // configure additional Hibernate Properties
}

in src/main/resources/application.properties:

dbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/myDb
jdbc.user=tutorialuser
jdbc.pass=tutorialpass

hibernate.dialect=org.hibernate.dialect.MySQLDialect
hibernate.hbm2ddl.auto=create-drop

in rc/test/resources/application.properties:

jdbc.driverClassName=org.h2.Driver
jdbc.url=jdbc:h2:mem:myDb;DB_CLOSE_DELAY=-1;NON_KEYWORDS=KEY,VALUE

hibernate.dialect=org.hibernate.dialect.H2Dialect
hibernate.hbm2ddl.auto=create

Test:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(
  classes = { StudentJpaConfig.class }, 
  loader = AnnotationConfigContextLoader.class)
@Transactional
public class InMemoryDBTest {

    @Resource
    private StudentRepository studentRepository;

    @Test
    public void givenStudent_whenSave_thenGetOk() {
        Student student = new Student(1, "john");
        studentRepository.save(student);

        Student student2 = studentRepository.findOne(1);
        assertEquals("john", student2.getName());
    }
}