Operational acceptance testing (OAT) is used to conduct operational readiness (pre-release) of a product, service, or system as part of a quality management system. OAT is a common type of non-functional software testing, used mainly in software development and software maintenance projects. This type of testing focuses on the operational readiness of the system to be supported, and/or to become part of the production environment. Hence, it is also known as operational readiness testing (ORT) or operations readiness and assurance testing (OR&A). Functional testing within OAT is limited to those tests which are required to verify the non-functional aspects of the system.

OAT elaborates upon and compartmentalises operational aspects of acceptance testing.^[1]

According to the International Software Testing Qualifications Board (ISTQB), OAT may include checking the backup/restore facilities, IT disaster recovery procedures, maintenance tasks and periodic check of security vulnerabilities.,^[2] and whitepapers on ISO 29119 and Operational Acceptance by Anthony Woods,^[3] and ISO 25000 and Operational Acceptance Testing by Dirk Dach et al., OAT generally includes:^[4]

• Component Testing
• Failover (Within the same data centre)

• Component fail-over
• Network fail-over

• Functional Stability

• Accessibility
• Conversion
• Stability
• Usability

• IT Service Management (Supportability)
• Monitoring and Alerts (to ensure proper alerts are configured in the system if something goes wrong)
• Portability

• Compatibility
• Interoperability
• Installation and Backout
• Localization

• Recovery (across data centres)

• Application/system recovery
• Data recovery

• Reliability

• Backup and Restoration (Recovery)
• Disaster Recovery
• Maintainability
• Performance, Stress and Volume,
• Procedures (Operability) and Supporting Documentation (Supportability)
• Security and Penetration

During OAT changes may be made to environmental parameters which the application uses to run smoothly. For example, with Microsoft Windows applications with a mixed or hybrid architecture, this may include: Windows services, configuration files, web services, XML files, COM+ components, web services, IIS, stored procedures in databases, etc. Typically OAT should occur after each main phase of the development life cycle: design, build, and functional testing. In sequential projects it is often viewed as a final verification before a system is released; where in agile and iterative projects, a more frequent execution of OAT occurs providing stakeholders with assurance of continued stability of the system and its operating environment.

An approach used in OAT may follow these steps:

• Design the system,
• Assess the design,
• Build the system,
• Confirm if built to design,
• Evaluate the system addresses business functional requirements,
• Assess the system for compliance with non-functional requirements,
• Deploy the system,
• Assess operability and supportability of the system.

For running the OAT test cases, the tester normally has exclusive access to the system or environment. This means that a single tester would be executing the test cases at a single point of time. For OAT the exact Operational Readiness quality gates are defined: both entry and exit gates. The primary emphasis of OAT should be on the operational stability, portability and reliability of the system.