Explain component testing and the process to write component cases.

Component testing is testing of a specific module or program.It may be done in isolation from the rest of the system depending on the life cycle model selected for that particular application.

Stub and driver are used for competent testing. These both are considered as components. Best example is given below : Suppose you are testing one application which has 3 modules called X ,Y and Z. and think that each module depends on above like Y is depends on X , Z it depends on Y. Now if the developer developed the Y module and as a tester if you want to test it then you need to use stub & driver as module X and Z. Based on the above example it will be easy to write a test case for you.