Applying Industrial-Strength Testing Techniques to Critical Care Medical Equipment

Abstract

Hardware and software development of embedded systems interdependently gear into each other. Even more so if the device under development is intended for use in critical care facilities such as intensive care units. Especially in this case, safety measures and risk mitigation techniques are implemented using both hardware and software components. Thus applying hardware and software testing approaches in combination is inevitable as well.

The increasing utilization of test domain-specific languages (Test DSLs), code generators and keyword-driven interpreters tends to raise the level of abstraction in test development. This approach aims to enhance productivity by generating executable tests from a non-programming language created for describing test cases. A second goal is to increase coverage by generating tests for as many as possible combinations of input values (black box test) or for all reasonable paths of a program flow (white box test). In combination with hardware-supported signal generation and fault injection this can be a very powerful strategy for testing safety-critical embedded devices. This article introduces an example of this strategy - the usage of a keyword-driven testing technique in cooperation with additional test hardware - in the context of an embedded medical device development, all the while emphasizing the benefit of combining different approaches. It discusses the utilization of commercial off-the-shelf (COTS) testing hardware as well as the application of an in-house developed test box. It also highlights the integration of commercial software - for requirements engineering, test management and continuous integration - with a self-developed testing framework powered by its own keyword-based test DSL.