User Acceptance Testing (UAT) is a process to obtain confirmation that a system meets mutually agreed-upon requirements. A Subject Matter Expert (SME), preferably the owner or client of the object under test, provides such confirmation after trial or review. In software development, UAT is one of the final stages of a project and often occurs before a client or customer accepts the new system.
Users of the system perform these tests, which developers derive from the client's contract or the user requirements specification.
Test-designers draw up formal tests and devise a range of severity levels. Ideally the designer of the user acceptance tests should not be the creator of the formal integration and system test cases for the same system. The UAT acts as a final verification of the required business function and proper functioning of the system, emulating real-world usage conditions on behalf of the paying client or a specific large customer. If the software works as intended and without issues during normal use, one can reasonably extrapolate the same level of stability in production. User tests, which are usually performed by clients or end-users, do not normally focus on identifying simple problems such as spelling errors and cosmetic problems, nor showstopper defects, such as software crashes; testers and developers previously identify and fix these issues during earlier unit testing, integration testing, and system testing phases.
The results of these tests give confidence to the clients as to how the system will perform in production. There may also be legal or contractual requirements for acceptance of the system.
