Actually it makes a lot of sense to separate your Production and Test projects into 2 separate entities, but have the same package structure in both projects.
So if I have a project 'my-project' I also create 'my-project-test', so I have the following directory structure:
my-project
+--- src/com/foo
my-project-test
+---test/com/foo
This approach ensures that test code dependencies do not pollute production code.
In my personal opinion, package private and protected methods should be tested as well as public methods. Hence I want my test classes in the same package as production classes.
