What is Regression Testing in Software Engineering?

Regression testing is a quality assurance process used in software engineering to ensure that changes, updates, or enhancements to a codebase do not introduce defects or disrupt the functionality of previously working features. It involves re-running functional and non-functional tests on the software after modifications are made.

Types of Regression Testing

• Retest-All: Re-examines all test cases to ensure software integrity. While thorough, it is resource-intensive.
• Regression Test Selection: Executes a limited subset of test cases based on the perceived impact of changes, saving resources compared to retesting all cases.
• Test Case Prioritization: Prioritizes test cases based on their importance or likelihood of detecting faults.
• Hybrid Approach: Combines regression test selection and test case prioritization techniques for efficiency.

Methods

Regression testing can be performed manually or automated:

• Manual Testing: Used for GUI-based tests where automation is challenging.
• Automated Testing: Commonly employed for repetitive tasks and large test suites using tools like Selenium or JUnit.

Benefits

• Detects bugs early, minimizing risks.
• Ensures compatibility between old and new functionalities.
• Supports agile development cycles by enabling frequent updates without compromising quality.

Challenges

• High resource consumption for exhaustive testing.
• Complexity in testing third-party components due to limited control.
• Managing large test suites as software evolves.

Example Application

Consider an e-commerce platform where a new product filter feature is added. Regression testing ensures that this update does not affect other functionalities like user login or payment processing.

In conclusion, regression testing is an indispensable part of software development, ensuring stability and reliability amidst continuous changes.