Topic: Learn Unit Testing--Benefits--Limitations

Definition: By knowing the inner logic the program the test what you conduct is Unit Testing. or Testing the piece/unit of a program

       Unit testing is a procedure used to validate that a particular module of source code is working properly. The procedure is to write test cases for all functions and methods so that whenever a change causes a regression, it can be quickly identified and fixed.

                   

Benefits: 

                        The goal of unit testing is to isolate each part of the program and show that the individual parts are correct. Unit testing provides a strict, written contract that the piece of code must satisfy. As a result, it affords several benefits.

            1) Facilitates Change

            2) Simplifies Integration

            3) Documentation

            4) Separation of Interface from Implementation

Limitations of Unit Testing:

                 Unit-testing will not catch every error in the program. By definition, it only tests the functionality of the units themselves. Therefore, it will not catch integration errors, performance problems or any other system-wide issues. In addition, it may not be easy to anticipate all special cases of input the program unit under study may receive in reality. Unit testing is only effective if it is used in conjunction with other software testing activities.

                 It is unrealistic to test all possible input combinations for any non-trivial piece of software. A unit test can only show the presence of errors; it cannot show the absence of errors. Though these two limitations apply to any form of software test.