What is the best and easiest way to integrate unit test library, QtTestLib, into existing Qt project with about 50 classes?

- Can I create for example 'test' folder under main project and put all test classes there including test application project file? How about including classes from existing project
- Do I have to copy from existing qt project file all the INCLUDES, LIBS, various CONFIGS into test application project file ?

Are there any example (large) projects where it is used?