JUnit is a unit testing framework for the Java programming language. JUnit has been important in the development of test-driven development, and is one of a family of unit testing frameworks which is collectively known as xUnit that originated with SUnit.
JUnit was originally written by Erich Gamma and Kent Beck. The latter literally wrote the book on Test Driven Development. I thought it would be worthwhile to look at some of the tests in the library and draw attention to some interesting things about them because it may change people’s ideas of how to practice TDD.