What is the typical order of testing levels?

The typical order of testing levels reflects the progression of software testing from the most granular level to the broader system-level assessments. Starting with unit testing, which focuses on verifying individual components or functions of the software in isolation, testers ensure that these pieces work correctly before integrating them into larger assemblies.

Following unit testing is system testing, where the complete integrated system is validated as a whole. This level of testing evaluates the end-to-end system specifications, confirming that the integrated components function together as intended.

Next comes acceptance testing, which assesses the software's performance in real-world scenarios and its compliance with business requirements. This level often involves end-users or stakeholders to ensure that the software meets their needs and expectations before it is deployed.

Lastly, maintenance testing occurs after the software has been released and is in use. This stage involves testing any updates, bug fixes, or enhancements made to ensure that the changes do not introduce new defects and that the software continues to meet its intended purpose.

This structured approach, from unit testing to maintenance testing, allows for effective risk management and helps to ensure software quality at each stage of development.