When are acceptance tests performed in relation to the system's installation?

Acceptance tests are performed immediately after installation to ensure that the system meets the defined requirements and functions as intended in the operational environment. This phase is critical because it allows stakeholders to verify that all components work together seamlessly and that the system fulfills its purpose before it is fully deployed or handed over for ongoing use.

Conducting acceptance tests at this stage helps to identify any issues or discrepancies that may have arisen during the installation process. It acts as a final verification step to confirm that the system is ready and acceptable for use by the end users. Addressing any potential failures right after installation reduces the risk of encountering significant problems when the system goes live.

In contrast, performing acceptance tests immediately before installation would not allow for the proper verification of system performance in its intended environment. Testing after the system is put into service may result in prolonged downtime or user dissatisfaction if issues are revealed. Testing only during maintenance would not provide any assurance before deployment, making it a less effective approach for ensuring system readiness.