Requirement 4: Robustness

Robust. The NPT should be thoroughly tested to ensure robustness on three fronts: (1) the NPT should be able to cope (without crashing) with a wide range of stress situations, and it should perform reasonably under important workload (queries and data discovery). User experience, both front end and back end, should be as intuitive and friendly as possible; any errors should be trapped and not seen by users, but systematically addressed as priority requirements or issues; (2) it should also allow the management of dependencies on external services (for example, external data calls).