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Case Study: Model-based Test Case Generation
Description of the example.
The example is taken from the MOGENTES
project [1], where the goal is the model-based generation of ecient test
cases. Demonstrators are from the field of automotive and railway, thus their
systems are real-time and safety-critical, and needs intensive testing. For
the formal specification of the model UML models are used with a precise
semantics. The structural parts are described by class diagrams, and the
behavior of the objects by state machines. During testing, the test goal is
to verify the fulfillment of the requirements related to the behavior, which
are associated to elements of the UML state machines. As real-time models
are considered, the state machines contain also time related transitions, and
their semantics is provided through a mapping to timed automata [16].
The test case generation process.
It is a common practice to use model check-
ers for generating test cases for state based systems. There is a COTS tool en-
vironment UPPAAL [17] for timed automata, thus we have transformed UML
models to timed automata, generated traces with UPPAAL that can be used
as test cases, and converted the traces to abstract test cases (ATC) which
have a pre-defined format and in which the concepts of the original UML
models are referenced. The transformation from UML to timed automata is
performed in two steps: first the hierarchical state machines are flattened to
Kripke-structures (so called SMTE models), and those are mapped to the in-
put language of UPPAAL. During the transformation a mapping file between
the concepts of UML and UPPAAL is also generated, which is used during
the conversion of UPPAAL traces to ATCs. The process is depicted in Fig. 2.
The deployment of the framework and the related components.
During the im-
plementation three tools are developed that provides four services: a transfor-
mation tool with two transformations (UML-to-SMTE, SMTE-to-UPPAAL),
a UPPAAL based tool generating a trace from a model if a test goal is pro-
Fig. 2. The process of timed automata based test case generation
