iBATIS best practices - iBATIS in Action - page 293

Listing 13.3 A unit test for the PersonDao with a mock SqlMapClient

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

Mock mock = new Mock(SqlMapClient.class);
mock.expects(once())
.method("queryForObject")
.with(eq("getPerson"),eq(PERSON_ID))
.will(returnValue(new Person (PERSON_ID)));

PersonDao daoSqlMap =
new SqlMapPersonDao((SqlMapClient) mock.proxy());
Person person = daoSqlMap.getPerson(PERSON_ID);

assertNotNull("Expected non-null person instance.",
person);
assertEquals("Expected ID to be " + PERSON_ID,
PERSON_ID, person.getId());
}

The example in listing 13.3 uses the JU nit as well as the JM ock object-mocking
framework for Java. As you can see in the bolded section, mocking the SqlMapCli-
ent interface with JM ock allows us to test the behavior of the DAO without worry-
ing about the actual SqlMapClient , including the SQL , the XML , and the database
that comes along with it. JM ock is a handy tool that you can learn more about at
www.jmock.org. As you might have already guessed, there is also a mocking frame-
work for . NET called NM ock, which you can find at http://nmock.org.

13.1.3 Unit-testing DAO consumer layers

The other layers of your application that use the DAO layer are called consumers .
The DAO pattern can help you test the functionality of those consumers without
depending on the full functionality of your persistence layer. A good DAO imple-
mentation has an interface that describes the available functionality. The key to
testing the consumer layer lies in having that interface. Consider the interface in
listing 13.4; you may recognize the getPerson() method from the previous section.

Listing 13.4 Simple DAO interface

public interface PersonDao extends Dao {
Person getPerson(Integer id);
}