D.Dranidis, K.Tigka, P.Kefalas


Formal Modelling of Use Cases with X-machines


Abstract: Use cases are a popular method for capturing the behavioral re-quirements of software systems. They are usually written in informal text form
describing the interactions between users and the system. Use cases are the cen-tral driving artifacts in Unified Process (UP), an agile software methodology.
Testing plays a very important role in UP and other agile methodologies, such as Extreme Programming. X-machines is a formal method for the specification of
systems. Furthermore, a method for testing systems specified by X-machines ex-ists that generates a complete test case set. This paper proposes the integration
of X-machines in the UML use case model, in order to facilitate the generation of a complete test case set for system testing. We present a transformation that
semi-automatically transforms use case text into its corresponding X-machine model and we demonstrate the transformation by using the example of an ATM.
We also suggest some improvements in the design of X-machine models, such as the use of compound inputs (consisting of interaction functions and data) and a
structured representation of the memory, giving an object-oriented flavor, and we discuss the benefits of these improvements.

Available: Copy on request from the authors.


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