Java EE 6 Integration Testing with Spring

Half a year ago, I created and published the jeeunit project to fill in some gaps for running integration tests on Java EE 6 components in an embedded EJB container, mainly targeted at Embedded Glassfish 3.x. One of the alternatives I considered and dismissed before writing my own solution was the Spring Test Context.

At the time, I was left with the impression you had to pollute your Java EE components with Spring annotations like @Transactional to make declarative transactions work in the Spring container, and I did not (and still do not) like the idea of writing XML just to create a couple of Java beans and wire them up.

After taking a closer look at Spring 3.0.x these days, I realized a number of facts which are not quite obvious from the Spring reference manual:

• You can do most of your Spring configuration (but sadly not all of it!) in Java instead of XML, which makes your application context type-safe and easier to read, and gives you refactoring support from your IDE.
• Spring supports some (but not all) of the Java EE 6 annotations as alternatives to its own flavours.
• You can run Stateless Session Beans and JPA entities in a Spring container with declarative transactions without introducing dependencies on Spring APIs or annotations.

jeeunit now includes an example project jeeunit-example-test-spring demonstrating this approach. The details are documented in the jeeunit Wiki page Testing on Spring.

This solution is not intended to replace the original in-container-testing approach of jeeunit, because transactional Spring beans and EJBs have different run-time semantics. However, for many integration tests, these differences are irrelevant.

Using the Spring Test Context instead of Embedded Glassfish and jeeunit has two main advantages:

• Spring starts noticeably faster than Embedded Glassfish.
• Launching a single test from your suite is much easier than with jeeunit. E.g. in Eclipse, you can simply use Run as JUnit Test just as with plain old unit tests.