Combining Risk Analysis and Slicing for Test Reduction in Open Architecture

Abstract

The Navys open architecture framework is intended to promote reuse and reduce costs.Relevant cost components include both planned test and evaluation effort and possible future failures of deployed software. Pairing system risk analysis using fault trees with NPS research on dependency analysis should enable these benefits and keep resource requirements at feasible levels. This paper describes methods that evaluate the risk impact of software components. The approach combines system risk analysis, dependency analysis applied to source code, and automated testing applied to executable component implementations. Determining the level of reliability required for each software component to achieve acceptably low system risk exposure is a key concern in this context, since the number of test cases required can be derived from this information. The paper applies open architecture principles to reduce testing effort and costs by finding the minimum testing effort required to reduce exposure to identified risks. When combined with our previous work on safe test reduction in cases where the requirements and code for a subsystem have not been changed, but the component will be used together with new or modified components, or may be reused in a different context with different operational loads and different system risk exposures, the results will enable further safe reductions in testing costs. These situations are common in the Navy due to technology advancement upgrades and policies that emphasize component reuse across systems.