Topic: Benefits of Unit Testing

The goal of unit testing is to isolate each part of the program and show that the individual parts are correct. It provides a written contract that the piece must satisfy. This isolated testing provides four main benefits:

Encourages change

Unit testing allows the programmer to refactor code at a later date, and make sure the module still works correctly (regression testing). This provides the benefit of encouraging programmers to make changes to the code since it is easy for the programmer to check if the piece is still working properly.

Simplifies Integration

Unit testing helps eliminate uncertainty in the pieces themselves and can be used in a bottom-up testing style approach. By testing the parts of a program first and then testing the sum of its parts will make integration testing easier.

Documents the code

Unit testing provides a sort of "living document" for the class being tested. Clients looking to learn how to use the class can look at the unit tests to determine how to use the class to fit their needs.