JUnit and TDD for Testing Let's combine the power of JUnit and TDD principles to make great automated execution code for testing. by Join the DZone community and get the full member experience.Join For Free I was asked a question from someone learning how to automate with Java. I’ve rewritten and paraphrased the question below. I see that JUnit is a way for a developer to write Unit tests because I want the outcome of the code to work as per assertions. JUnit is for Unit Testing. And Unit tests are written by developers. When will a tester use JUnit?