When designing a system, it is necessary to capture requirements. Various approaches can be used for this, but currently there are no mechanisms that enable the requirements to be documented in such a way to enable an implementation to be validated back against the requirements.

The SAVARA tools provide a means of describing requirements, representing specific use cases for the interactions between a set of cooperating services, using scenarios - which can be considered similar to UML sequence diagrams that have been enhanced to include example messages. In the purchasing Eclipse project, the SuccessfulPurchase.scn scenario looks like this:

The business requirements can therefore be defined as a set of scenarios, each demonstrating a specific use-case, or path through the business process being enacted.

It is also possible to define scenarios that represent invalid use cases, that should not be implemented by the system. In these cases, the invalid message events (i.e. the sending or receiving icons) will be flagged as "Error Expected", to indicate that they should not occur.