Verify that existing functionality should not be changed if 1. Any   new feature added or modified 2. Any defect fixed 3. Any performance issue fixed

Definition

When to do regression testing?

1. When adding new functionality into the application. Exa: Login Page - Add Forgot Password Link Feature

When to do regression testing?

2. When change the requirements in the application. Exa: If the remember password functionality removed from the login page.

When to do regression testing?

3. When the defect fixed. - Exa: After fixing and retesting the defect, regression testing can be performed.

When to do regression testing?

4. When performance issue fixed. Exa: After fixing performance issue, web page access time decreases up to 3 to 5 sec

Regression Testing Technique: 

Test Case Prioritization 

Complete Regression 

Regression Test Selection 

Main Focus 

The main focus on the regression testing is that application should be working as expected.