A Workflow for Automated Testing of a Safety-Critical Embedded Subsystem

As embedded systems in safety-critical domains, such as transportation, become increasingly complex, ensuring their reliability thorough testing becomes essential. Manual testing methods are often time-consuming, error-prone, and inadequate to cover all possible failure scenarios, especially in systems that require a high level of functional safety and robustness. To address these challenges, the need for automation in the testing process is evident, particularly for real-time, embedded, and hardware-dependent systems where validation is crucial for ensuring safe operation.This paper proposes a structured workflow for automating the testing of a safety-critical embedded subsystem, utilizing a real hardware-in-the-loop (HIL) environment. The approach covers all major phases of the testing process, including test specification, execution, and results assessment. The inspiring idea is to try to shift the focus of intellectual effort toward the early stages of the validation process, facilitating a clear and shared understanding between testers and developers regarding the system's behavioral and functional requirements.The first phase involves creating a detailed test specification, which includes: developing a behavioral model of the feature to be validated; defining data probes for monitoring the subsystem under test; creating simulation scenarios to provide stimuli to the subsystem’s external interfaces. In the second phase, executable test scripts are generated either automatically or semi-automatically using multi-technology scripting languages, followed by the creation of a sequence of test cases. The final phase involves executing the tests on the actual hardware platform, collecting execution logs, and running automated checks to evaluate the results.The workflow and tools are evaluated using a case study of the onboard subsystem hardware and software platform developed by Hitachi Rail.