iBATIS best practices - iBATIS in Action - page 294

The interface in listing 13.4 is all we need to begin testing the consumers of our
DAO layer. We don't even need a completed implementation. Using JM ock, we
can easily mock the expected behavior for the getPerson() method. Consider the
service that makes use of the PersonDao interface (listing 13.5).

Listing 13.5 A service that makes use of PersonDao

public class PersonService {

private PersonDao personDao;

public PersonService(PersonDao personDao) {
this.personDao = personDao;
}

public Person getValidatedPerson(Integer personId) {

Person person = personDao.getPerson(personId);

validateAgainstPublicSystems(person);
validateAgainstPrivateSystems(person);
validateAgainstInternalSystems(person);

return person;
}

}

The target of our unit tests is not the DAO —it's the getValidatedPerson()
method logic, such as the various validations it performs. Each of the validations
may be a private method, and for argument's sake, let's just agree that we're only
testing the private interface here.
Testing this logic without a database will be easy, thanks to that PersonDao inter-
face that we saw earlier. All we need to do is mock the PersonDao , pass it to the con-
structor of our service, and call the getValidatedPerson() method. Listing 13.6
shows the unit test that does exactly that.

Listing 13.6 Using a mock instead of the real DAO to avoid hitting the database

public void testShouldRetrieveAValidatedPerson (){
final Integer PERSON_ID = new Integer(1);

Mock mock = new Mock(PersonDao.class);
mock.expects(once())
.method("getPerson")