Acceptance Testing
Acceptance testing checks whether a system meets the agreed business requirements and is ready for delivery, typically the last test level before release. It's a validation activity — confirming the right product was built — often performed by or with input from the actual stakeholders or users the software is for.
Acceptance testing sits at the top of the traditional test-level pyramid: unit, integration, system, then acceptance. By this point functional correctness has (ideally) already been verified at lower levels — acceptance testing is less about finding new bugs and more about confirming the whole system satisfies the actual business need it was built for.
User Acceptance Testing (UAT) is the most common form, run by real or representative users. Other variants exist for different audiences: contract acceptance testing (does it meet a contractual spec) and regulatory acceptance testing (does it meet compliance requirements) — same underlying idea, different judge.
