Principles of Built-In-Test for Run-Time-Testability in Component-Based Software Systems

This paper examines the motivations and expectations of Built-In-Test (BIT) techniques for Run-Time-Testability (RTT) in component-based software systems. The difficulties associated with testing and integrating fully encapsulated components lead to a requirement for testing interfaces. The format of these interfaces is explored at a high level of abstraction, and some possibilities for Built-In-Test (BIT) are described. BIT is concerned with the detection of error conditions arising internally to a component, or arising from erroneous component interactions, and the propagation of these error conditions to a system component having responsibility for error handling and/or recovery. The implications for testability, reliability and maintainability are discussed, and it is concluded that BIT offers potential for improved product quality. Whilst the proposed approach is considered appropriate for a wide range of software systems, issues related to real-time systems, such as deadlock and timing constraints are of particular interest.