如何在Eclipse中使用JUnit ?

I am a long time user of Eclipse but a novice when it comes to JUnit. I have lots of java projects and I want to start writing test cases around the methods in those projects. I'm just wondering the best way to set up the Eclipse environment for this purpose. Let's assume I have a typical project with a typical src directory in a specified package. How do I attach test cases to that project. Some concerns: 1. I don't want the test cases to be part of any build that I create on the project. 2. I want to refer to the clases in the test-suite. I am a long time user of Eclipse but a novice w