Unit testing is done by developers who write tests while building any software.  It is a simple but effective idea that improves time-to-market, flexibility and the quality of any software released in the market.

Preferably, each developer should produce a set of tests to validate each individual method and class as they are being written. It takes time to identify all the scenarios, write tests, run test cases and monitor the results. Also, writing unit tests by hand is expensive, labor intensive, tedious, and still leaves the possibility that many of the execution paths are not tested and remain incomplete. 

This paper elaborates a simple approach on how unit test case generation can be automated, helping the developers in reducing the amount of engineering hours needed, while at the same time increasing both completeness of the test coverage and the software quality.