It is not enough to thoroughly test each area of the program one time only – it must be repeatedly tested on a regular basis. The program is constantly changed, therefore new problems arise, the old errors occur again. Regression testing should cover the program as completely as the initial testing itself, but it must not take so much time as the latter.
First of all, a regression test suite should include test cases that verify all the recent software updates and patches. This set is not always the same, certainly, the tests are included in it, and then, some time later, they are removed, as the new tests replace them. Most of the regression tests are performed once or twice. However, there is a more permanent subset of tests that are the basis of regression test suite.
Regression testing services are often used to make sure that the software still works correctly after it has been changed or modified.
There must not be many regression tests – only the necessary number of test cases, fully covering the selected area of the program. They should, as far as possible, cover all aspects of this area (sub-program, boundary conditions, etc.) and all situations that cause failures and errors. Furthermore, it is desirable that these tests be rapid.
Of course, in practice, it is too difficult to fulfill the requirement of “get maximum coverage in minimum of time for the testing”. You should include the most interesting and useful tests in the set to check whether or not all the reported errors have been successfully fixed. Running basic and informal testing, include the best tests in a regression test set. The remaining tests are to be developed in the planning process. At least the half of its time should be devoted to the tests to be carried out several times.
Testing service providers execute various tests on demand. They are asked to perform regression testing to ensure that recent changes have not adversely affected the existing functionality.
It is reasonable to consider the following regression testing strategy: some of the tests are performed for each version of the program, the others – for each second or third its version, the third – even more rarely. This will help to speed up the testing process, maintaining full coverage of the program. Toward the end of development, when the new program versions may become available for testing more and more frequently, the described method will stand you in good stead.
Software development quality assurance is meant to verify and validate the project continuously. It is much cheaper to identify and remove software defects in earlier stages of the development. By doing so you can incorporate quality in this process and save on its costs.