Re: junit test for entity beans ... ejb 3.0

Question

I'm confused. I'm trying to test my entity bean.
I have:
- an entity bean
- a stateless session bean for accessing the entity bean (facade)
- an interface for accessing the the stateless bean
And I'm trying to write a JUnit test class to test this bean. However, I am uncertain as to how to test this (I'm new to EJB 3.0, JBoss and Eclipse).
What would the JUnit test look like? I'm confused as to whether or not I should be injecting the interface/bean/what???
I've tried several variations. I either get "NameNotFound" - not bound exceptions or Null pointer exceptions.
What would the @EJB syntax look like or how would I do it through the context?
For Example:
@EJB private TestFacade myTest; //interface to stateless bean ?
OR
InitialContext ctx = new InitialContext();
TestResultFacadeBean myTest = (TestResultFacadeBean) ctx.lookup("localTest");
I'm confused at to which method I should be using and what object I should be accessing. If I could get either one to work, I'd be happy. :)
How do I ensure my bean is deployed to the container? What do I need to do?
If anyone has a simple example or explanation as to which method I should use and how to use it, I'd be very grateful.
Thanks very much,
LisaD

Answer 1

OK, you need to have several layers of testing.
Layer 0. Test the entity beans are deployable (more on this later). Basically, you need to know that all your annotations work. Things to watch out for are multiple @Id fields in one class or @EmbeddedID or @IdClass in conjuction with @ManyToOne, @ManyToMany, @OneToMany, @OneToOne and fun with @JoinTable, @JoinColumn and @JoinColumns. Once you know how these are supposed to work with the spec, it's not too bad to write it correctly each time. But there are some gotchas that will break things later on.
Layer 1. Do the functions in the classes that don't depend on annotations work as expected. Typically, this is just going to be the getters and setters in your entity classes. Of course JUnit best practice says we don't bother testing functions that look like:
public T getX() {
return this.x;
or
public void setX(T x) {
this.x = x;
as there is nothing that can go wrong with them. So in that case, your level 1 tests will just be initial values specified from constructors and verifying that the non-get/set pairs work, and that the getters you have tagged @Transient work (because you've likely put some logic in them)
Layer 2. Test the session bean methods that don't require injection to work.
Layer 3. Test the session bean methods that require injection (Mock Objects). Simulate the injection for yourself, injecting Mock Objects for the entity manager. Then you can confirm that the correct methods are being called in the correct sequences, etc.
[Note this may require some skill in designing the mock.  I'm working on developing my own entitymanager mock, and if it looks usefull I'll release it to the world.
Layer 4. Test the session bean methods that require injection (Real entity manager) (See Layer 0)
For this you will need an out of container persistence implementation.  Currently Hibernate and Glassfish provide beta versions.  You will need a different persistence.xml file that lists all the entities.  You will have to use reflection to inject the entity manager(s) that you create from an entity manager factory unless you provide a constructor that takes an EntityManager as a parameter.  You may need to use reflection to call any @PostConstruct method if you made it private.
Layer 5. Navigate the relationships in the objects returned from Layer 4 using a database that has been loaded with test data.
I am currently using Layers 0, 1, 2 & 4 to test my session beans and entity beans.