Spring/Hibernate/Junit example of testing DAO against HSQLDB

Question

I'm working on trying to implement a JUnit test to check the functionality of a DAO. (The DAO will create/read a basic object/table relationship).

The trouble I'm having is the persistence of the DAO (for the non-test code) is being completed through an in-house solution using Spring/Hibernate, which eliminates the usual *.hbm.xmltemplates that most examples I have found contain.

Because of this, I'm having some trouble understanding how to setup a JUnit test to implement the DAO to create/read (just very basic functionality) to an in-memory HSQLDB. I have found a few examples, but the usage of the in-house persistence means I can't extend some of the classes the examples show (I can't seem to get the application-context.xml setup properly).

Can anyone suggest any projects/examples I could take a look at (or any documentation) to further my understanding of the best way to implement this test functionality? I feel like this should be really simple, but I keep running into problems implementing the examples I have found.

edit:

Here's my solution for better readability, for anyone who needs a hand getting things going:

• My TestClass:

  @RunWith(SpringJUnit4ClassRunner.class)
  @ContextConfiguration(locations = "classpath:applicationContextTest-Example.xml")
  @Transactional
  public class ExampleDaoTest extends AbstractTransactionalJUnit4SpringContextTests {
      @Resource(name = "sessionFactory")
      private SessionFactory exampleSessionFactory;
  
      @Resource(name = "exampleDao")
      private ExampleDao exampleDao;
  

• My applicationContext.xml file:

  <!-- List of Daos to be tested -->
  <bean id="exampleDao" class="org.myExample.ExampleDao"/>
  
  <!-- Datasource -->
  <bean id="example_dataSource"
        class="org.apache.commons.dbcp.BasicDataSource">
      <property name="driverClassName" value="org.hsqldb.jdbcDriver"/>
      <property name="url" value="jdbc:hsqldb:mem:ExampleTest"/>
      <property name="username" value="sa"/>
      <property name="password" value=""/>
  </bean>
  
  <!-- Session Factory -->
  <bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
      <property name="dataSource" ref="example_dataSource"/>
      <property name="annotatedClasses">
          <list>
              <value>org.myExample.ExampleClass</value>
          </list>
      </property>
      <property name="hibernateProperties">
          .... left to user to choose properties
      </property>
  </bean>
  

Answer 1

Spring 3 offers a new jdbc namespace that includes support for embedded databases, including HSQLDB. So that takes care of that part.

I'm wondering what the "in-house solution" could be. You can use annotations (either JPA or Hibernate annotations) to ORM your domain objects, so why do you need an "in-house solution"? E.g.:

<bean id="sessionFactory"
    class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean"
    p:dataSource-ref="dataSource"
    p:packagesToScan="myapp.model" />

As far as implementing a test goes, use Spring's TestContext Framework. A test can look like this (again I'm assuming Spring 3 below, though it should work in Spring 2.5 simply by changing @Inject to @Autowired):

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({
    "/beans-datasource-it.xml",
    "/beans-dao.xml",
    "/beans-service.xml",
    "/beans-web.xml" })
@Transactional
public class ContactControllerIT {
    @Inject private ContactController controller;

    ... setUp() and tearDown() ...

    @Test
    public void testGetContact() {
        String viewName = controller.getContact(request, 1L, model);

        ... assertions ...
    }
}

You'd put the embedded database inside beans-datasource-it.xml, for example. ('it' here stands for integration test, and the files are on the classpath.) The controller in this example lives in beans-web.xml, and will be autowired into the ContactController field.

That's just an outline of what to do but hopefully it's enough to get you started.