MT - 69 - Regression testing and its types !

Regression Testing is a testing of a program which was previously tested and went through any modification. It is done to ensure that the defects have not been introduced or new defects has not been uncovered in the other areas of the program. It is performed when a software or its environment is changed. Regression testing is the process of testing changes to computer programs to make sure that the older programming still works with the new changes. They are subcategorised into 3 types :

Unit regression testing:
Testing the only one particular fixed unit or feature .

Region regression testing:
Testing the changes and the impact regions is called Regional Regression testing. In this type of regression testing only select modules are tested which are connected to the changed modules

Full regression testing:
Testing the changes and all the remaining features of the system.It is normally done when the changes are done in the root of the product or whenever the modifications or changes are more in the product or a larger area of the product is impacted.

Excerpts :
If any modification is done in one module and if the module is some where linked with the other two modules , then in this case regional regression is preferred over the full regression testing.If modifications are done in many modules in the project and if its difficult to recognize the effected modules then we do full regression testing rather than taking risk.