What is the primary purpose of user acceptance testing (UAT)?

User acceptance testing (UAT) plays a crucial role in the software development lifecycle because it verifies that the solution meets business needs and requirements from the end users' perspective. The primary purpose of UAT is to ensure that the system works as expected in a real-world environment, allowing users to validate whether the solution aligns with their requirements and expectations before it is deployed.

During UAT, end users interact with the application to identify any issues or discrepancies between the system's functionality and the business processes it is intended to support. This process ensures that the users are satisfied with the product and allows them to provide feedback or suggest enhancements before final implementation. UAT is typically the last phase of testing that confirms usability and effectiveness, ensuring that users are equipped to engage with the system confidently.

Other options, while relevant to testing, do not capture the primary focus of UAT. For instance, validating existing historical data is more aligned with data migration or integrity tests, testing the system after an update pertains to regression testing, and checking performance against service-level agreements focuses on system performance metrics rather than user satisfaction.