In some instances, such as production problem resolution or releases, user testing may have been performed during integration testing. All user acceptance testing is done in a test environment. If there are several libraries in test, user testing should reserved for one of the testing environments. Verify valid data flows through the system correctly and invalid data is handled appropriately. Check all edits, validation rules, default values, error messages and warning messages.
Validate system controls such as error file handling or duplicate entry processing.
Make sure response times for processing are acceptable. Ensure disaster recovery procedures are put in place. Assure system can handle high volumes. Verify data transmission to and from system are successful. This phase of testing is performed in the production environment after all programs, modules, JCL procedures, etc., have been implemented via the LSR process.