The popularity of JUnit grew exponentially, to provide to the needs of a lot of other contemporary languages such as C#, Perl, Python, PHP, Ruby, Visual Basic, C++, and many other languages. A generic xUnit framework was designed and developed where the letter 'x' is replaced by the first letter of the language, such as JUnit for Java, RUnit for Ruby, and so on. This article provides an overview of this framework as used by the de-facto standard of Java unit testing. It is extremely important that a code goes through the rigorous of various phases of testing. The unit testing as the name suggest, apart from its importance, it is also very commonplace.