Testing JPA-based applications - JUnit in Action - page 363

public class UserDto {
private long id;
private String username;
private String firstName;
private String lastName;
// getters and setters omitted
}
Finally, because the persistence layer will be developed using JPA , a new implementa-
tion ( UserDaoJpaImpl ) is necessary, and its initial version is shown in listing 18.3. 3

Listing 18.3 Initial implementation of UserDao using JPA

public class UserDaoJpaImpl implements UserDao {

private EntityManager entityManager; // getters and setters omitted

public void addUser(User user) {
entityManager.persist(user);
}

public User getUserById( long id) {
return entityManager.find(User. class , id);
}

public void deleteUser( long id) {
String jql = "delete User where id = ?";
Query query = entityManager.createQuery(jql);
query.setParameter(1, id);
query.executeUpdate();
}

}
The sample application is available in two flavors, Maven and Ant. To run the tests on
Maven, type 'mvn clean test' . Similarly, to use Ant instead, type 'ant clean test' .
The application is also available as two Eclipse projects, one with the required libraries
(under the lib directory) and another with the project itself.

18.1.2 Multiple layers, multiple testing strategies

Because each application layer has different characteristics and dependencies, the lay-
ers require different testing strategies. If your application has been designed to use
interfaces and implementations, it's possible to test each layer in isolation, using
mocks or stubs to implement other layers' interfaces.
In our example, the business layer façade (listing 18.4) will be tested using Easy-
Mock as the implementation of the DAO interfaces, as shown in listing 18.5.

3

The astute reader might be wondering why we listed UserDaoJpaImpl in this chapter but omitted
UserDaoJdbcImpl in chapter 17. The reason is that the JPA implementation is much simpler, just a few lines
of nonplumbing code.