Regression testing is testing done by the tester which is modification done by the developers. Three types of regression testing that is namely unit regression testing, regional regression testing and full regression testing.

1. Regression Testing
 This testing done by tester when the developers makes changes like addition of code ,deletion of
code and modifications in code in application.
 This testing ensure that new code changes do not have side effects on the existing functionalities.
 Regression testing done at the last few days of the sprint
 Regression testing is a black box testing techniques.
Types of Regression Testing
1. Unit Regression Testing
2. Regional Regression Testing
3. Full Regression Testing

2. Unit Regression Testing
 Unit regression testing, tests the code as a single unit which is changed by
developer.
 It has a narrow and focused approach
Regional Regression Testing
 It involves testing the modification together with the effect area or
areas.
 We're testing the impact area because if there are dependable
modules, they'll have an impact on the other modules as well.
Full Regression Testing
 Testing the modified features and all the remaining (old)
features is called the Full Regression testing.