JPA-based JUnit Test Best Practices

This is a bit of an odd question, but it has been bothering me for a few months now. I have built a JPA-based web application using Wicket + Hibernate (built with Maven), and want to test the DAO layer directly. I created a specific src/test/resources/META-INF/persistence.xml file that I used for testing, but have been running into conflicts with WTP and the like. To get around these issues, I created a separate test project where the unit tests live. Is there a better way to manage unit tests for a JPA project without having duels between persistence files?