/ˈtɛstɪŋ/
noun — "proving your code works… before someone else finds out it doesn’t."
Testing is the systematic process in information technology of evaluating software to ensure it behaves as expected, meets requirements, and is free of defects. Testing helps detect bugs, validate functionality, and improve reliability, performance, and security before deployment.
Technically, Testing involves:
- Unit testing — verifying individual components or functions of code.
- Integration testing — checking how different modules interact.
- System testing — evaluating the complete application as a whole.
- Regression testing — ensuring new changes do not break existing functionality.
- Automated vs manual testing — using scripts and frameworks or manual evaluation depending on requirements.
Examples of Testing include:
- Running a Python unit test to confirm a function returns expected output.
- Validating a web application’s workflow with automated Selenium scripts.
- Performing load tests to measure performance under heavy traffic conditions.
Conceptually, Testing is the quality gatekeeper of software—it catches problems before users do and ensures that programs perform reliably in the real world.
In practice, Testing integrates with debugging, logging, and continuous integration pipelines to maintain high code quality and operational stability.
See Debugging, Logging, Unit Testing, Integration Testing, Continuous Integration.