I have three projects in my C# 4 solution.
- MooDB: Has my domain objects in, NHibernate mappings, presentation classes.
- Data: Has my data access layer classes (using NHibernate)
- Test: Has my test classes
Here's a screenshot:

I've noticed that I've got app.config and hibernate.cfg.xml in my Test project. This does seem right. I don't have an app.config in my Data project which is a problem because I want to use log4net in my Data project but I can't configure it if there's no app.config there.
What's the best way to set up my solution? Should there be an app.config for each project or for the solution as a whole? Do I need one for my Test project? Have I organized it according to "best practise"?