why should we do regression testing ?

Regression testing is selective retesting of the system with an objective to ensure the bug fixes work and those bug fixes have not caused any un-intended effects in the system.

Goals:

The goals of regression testing are to check the bug fixation of the previous build and also to ensure that the bug fixes have not caused any unintended defects in the same or other modules of the build in test.

The objectives of Regression testing are to:

1.   Partially validate the system (i.e., to determine if it fulfills its operational requirements).

2      Cause failures concerning the operational requirements that help identify defects that are not efficiently found during unit and integration testing.

3       Report these failures to the development teams so that the associated defects can be fixed.

4       Help determine the extent to which the system is ready for launch.

5       To check if the bug fixes have caused further bug in the same or other modules of the product

6        Provide input to the defect trend analysis effort.

preconditions for regression testing

 Regression test execution can begin when the following preconditions hold:

1        The operational requirements to be tested have been specified and fully implemented.

2        The relevant software components have passed unit testing and one cycle of functional testing

3       Bug for the earlier builds have been posted and acted up on.

4       The test team is adequately staffed and trained in functional testing and regression testing

5       The test environment is ready.

6       The regression test set, as identified during planning/test case authoring phase is ready.

7       The bug reporting procedure and communication protocol is ready.