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Testing Railway Interlockings with. TT-Medal Review Berlin, Germany September 28, 2005. N. Ioustinova, J. van de Pol, N. Goga Centrum voor Wiskunde en Informatica Amsterdam, The Netherlands. This work is done in cooperation with ProRail. Goal.
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Testing Railway Interlockings with • TT-Medal Review • Berlin, Germany • September 28, 2005 N. Ioustinova, J. van de Pol, N. Goga Centrum voor Wiskunde en Informatica Amsterdam, The Netherlands This work is done in cooperation with ProRail
Goal Provide a framework for testing railway interlockings with TTCN-3 Railway Control System Apply the framework for testing interlocking software for Hoorn-Kersenboogerd station
Development of Test Cases standards test suite for interlocking on railway safety of Hoorn-Kersenboogerd 8 10 1 3 5 7 9 11 4 2 6
Development of Test System SUT TTCN-3 Test System for railway interlockings Interlocking Simulator Interlocking Program Special feature: time control simulated time Simulated time solution is based on Dijkstra’s distributed termination detection algorithm
FAIL Test Execution: Normal Train Departure Final situation: train at 66B and 68 remains yellow Initial situation: train on 66C Expected trace 66C 66B 66A 74B Setting the initial situation costs 21 cycles. Failure is detected in 1 cycle. 68 60 Observed trace 66C 66B 66A 74B 60 68
Market Relevance • In the European railway sector, the current target is to increase the proportion of railway transportation by 100-150% within a short period (www.railway-technology.com) • European integration (www.euro-interlocking.org) requires new standards for specification (UML) and testing (TTCN-3) • TTCN-3 enables to bring together • Vendors • Standardization • Certification • Operators in EU
TTCN-3 for the Railway Domain Advantages • Standardization: a standard language to specify test suites for railway applications • Reusability: one test suite can be used to test software from different vendors • Independency from implementation details of simulators for railway software • Automation of test execution for railway domain Benefits • High-quality test suites →reliable railway control systems • Reduction of costs for testing on the long run
Conclusions • We translated a subset of CENELEC safety requirements into TTCN-3 test cases. • TTCN-3 is suitable to specify test cases for railway control systems • According to ProRail, TTCN-3 is a significant step towards automation and standardization of testing process in the railway domain • TTCN-3 test system is extended by time simulation option • We have covered whole test-process starting from developing test cases, proceeding with implementing the test system and finally executing tests and interpreting results • Using this approach we found violations of general safety requirements