Test case design for the validation of component-based embedded systems

Abstract

The validation of functional and real-time requirements of control software for embedded systems is a difficult task. It usually needs the electronic control unit (ECU) and the controlled hardware components. But very often the ECU or hardware components are not available for testing the control software at the beginning of the development. This paper presents how test cases can be designed from use cases and how component-based control software can be validated without ECU and hardware components by simulating the test cases in early development phases. For achieving a tool-based testable format, extended UML sequence diagrams are applied to formalise sequences of events, which have been specified in the use case scenarios. Provided that black box components are used for developing component-based applications, the monitoring of the dynamic behaviour inside the components is not possible during simulation. But the simulated dynamic behaviour is observable on the connections between the software components. In such a way monitored and recorded time stamp events are finally compared offline against the expected sequences of events specified in the test cases. The offline comparison validates the simulated behaviour by demonstrating the fulfilment of user requirements and by detecting errors in case of contradictions. An application example of an automotive wiper control system demonstrates the capacity of the presented test case design and validation process. © 2001 by Springer Science+Business Media New York.