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.
