Definition: Unit testing is a development procedure where programmers create tests as they develop software. The tests are simple short tests that test functionality of a particular unit or module of their code, such as a class or function.
Using open source libraries like cunit, cppunit and nunit (for C, C++ and C#) these tests can be automatically run and any problems found quickly.
As the tests are developed in parallel with the source code, when the particular unit is completed, a successful unit test demonstrates it's correctness.
