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.xml`templates 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 i…

Accepted Answer

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.

Spring/Hibernate/Junit example of testing DAO against HSQLDB

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