Nowadays, we are using many semi or fully automated software applications in our day to day life. Qualitative, robust and trustworthy software are ensured by efficient testing. So, maintaining the quality of software is a crucial issue in our modern society. A huge number of software are developed for critical systems to support our everyday life including vending machines, automated traffic system and most electronic appliances. Developers are repeatedly trying to keep the software quality as high as possible through rigorous testing, which makes testing as the most important phase of Software Development Life Cycle (SDLC). In testing phase, different levels of testing are done for the Software Under Test (SUT), i.e. unit testing, integration testing, system testing and acceptance testing. Out of these testing techniques, unit testing which involves the testing process of a unit or a module, is the basis of all other testing techniques. During unit testing, if any error goes unidentified, then the error may propagate to the other modules.