Unit testing a Hibernate driven application? [closed]

Answer 1

As for best practices:

use an embedded database for running your tests if possible, so that you don't need a full deployed relational database just to run your tests (locally, or on your continuous build server if you have one). That way you also don't need to (necessarily) worry about rolling back etc, you can just recreate the database when you need to. Testing with an embedded database doesnt test peculiarities that could come up when you use your specific production database, but it does test your code, which should suffice.

You can also use DbUnit, an extension to JUnit, to easily fill the database with expected rows and put it in a known state, before you run your Hibernate tests.

Answer 2

You could use Spring to help here.

It has a great unit test framework, you can use it to test CRUD ops and then rollback changes - great if you don't have the capability to reload a database every time.

Answer 3

Keep in mind the difference between unit testing and integration testing.

Unit tests should be testing code without any outside dependencies. These dependencies are mocked using a framework like, for example, JMock.

Integration tests are important too but the major drawback of them is that they take a long time to run. You can run thousands of true unit tests in a couple of seconds, but it's not the same with integration tests.

Depending on the size of your project/development team you might want to prioritize true unit tests over integration tests. Both style of tests are important but if you are pressed for resources, just going with Unit testing may be a better idea.

I wrote an application by myself that unit tested the Web (with Spring MVC this is easy) and Service layers, as well as domain objects. But I left the DAO alone because I didn't want to write a bunch of slow integration tests. If I had more people on staff I would have gone with integration tests as well, but in this case I didn't feel the time spent would be worth it.

Answer 4

Write a simple layer that passes requests to Hibernate. Then use a mocking library like EasyMock or JMock to assert that your Hibernate-veneer layer is correctly called by your application classes. This is nicely described in the partially-complete JMock book (scroll down to the test smell "everything is mocked").