What is regression testing?

Regression testing is a type of software testing that involves re-running functional and non-functional tests to ensure that previously developed and tested software still performs correctly after it was changed or interfaced with other software. The purpose is to ensure that new changes haven’t introduced any new faults, or regressed, into existing functionality. This is crucial for maintaining the quality and stability of the software over time.

This form of testing is often performed after patches, enhancements, or other modifications are made to the software application, to validate that the new changes have not adversely affected existing functionality. It can be executed manually or through automated testing tools, depending on the testing strategy of the development environment.

Key aspects of regression testing include:

1. Test Selection: Choosing the appropriate tests from the test suite that might be affected by the code changes to ensure a thorough regression test.
2. Test Execution: Running the selected tests either manually or using automated testing frameworks/tools.
3. Result Analysis: Analyzing the outcomes of the regression tests to identify any failures caused by the recent code modifications.
4. Maintenance of Test Suite: Regularly updating the test suite to ensure it remains effective in catching regressions. This includes adding new tests for new features and updating or removing tests as necessary.

Regression testing is an ongoing process in the software development life cycle, as it needs to be conducted every time there is a change in code to ensure the software’s integrity. Depending on the size and complexity of the project, regression testing can