Unit testing is an important element of testing software.
In object-oriented software development, this term commonly refers to testing individual classes. In the simplest and most widely followed testing practice, developers of classes are expected to perform unit and integration testing of their respective classes before releasing their library to other groups. The test team is responsible for system testing before releasing the application to clients. Because class testing is the starting point of testing object-oriented software, understanding the issues involved and devising a way to perform effective class testing is a crucial first step in delivering high quality software. We believe this model can make class testing more interesting and effective.