What are the different levels of testing?

The different levels of testing are:

�             Unit Testing

�             Integration Testing

�             System Testing

Unit Testing: The unit testing is done to test the individual module of the software. Test cases are designed to test the program logic, functionality, interfaces etc. in a module. Since individual module is being tested, white box testing techniques are used here. Wherever required, stubs and drivers are also written to test the module, which increase the cost of the testing.

Integration Testing: In this the module are systematically integrated and tested to find interface problems, protocol design error, errors due to global values, input/ output format errors etc. Different strategies can be:

�              Bottom up Integration: In this type of testing the modules at the leaf level are first tested and then we move up in the hierarchy. Drivers are used in this type of testing at different levels of hierarchy. Driver is a program which accepts the test case data to be inputted and printed by the module to be tested.

�              Top Down Integration: In this case we start the top most module in the hierarchy and move down till the leaf modules are tested. Where ever required necessary stubs/ drivers are used. A stub is a program which simulates the module called by the module to be tested.

The different levels of testing are:

�             Unit Testing

�             Integration Testing

�             System Testing

Unit Testing: The unit testing is done to test the individual module of the software. Test cases are designed to test the program logic, functionality, interfaces etc. in a module. Since individual module is being tested, white box testing techniques are used here. Wherever required, stubs and drivers are also written to test the module, which increase the cost of the testing.

Integration Testing: In this the module are systematically integrated and tested to find interface problems, protocol design error, errors due to global values, input/ output format errors etc. Different strategies can be:

�              Bottom up Integration: In this type of testing the modules at the leaf level are first tested and then we move up in the hierarchy. Drivers are used in this type of testing at different levels of hierarchy. Driver is a program which accepts the test case data to be inputted and printed by the module to be tested.

�              Top Down Integration: In this case we start the top most module in the hierarchy and move down till the leaf modules are tested. Where ever required necessary stubs/ drivers are used. A stub is a program which simulates the module called by the module to be tested.