Prioritized MC/DC Framework for Early Fault Detection in Safety-Critical Software

Modified Condition/Decision Coverage (MC/DC) guarantees each written code block is effective in the final software product. A practical outcome of MC/DC validation is the increased verification time. When coverage is tested from top to bottom, faults may be detected late. This fact unintentionally adds resistance to project schedule. On the other hand, late fault-detection could be omitted by prioritizing test cases based on recently modified code blocks. Additionally, ordering covered code blocks based on their cyclomatic complexity, Halstead volume, coverage time, and function call frequency affects verification time. Time to First Fault Detection (TTFFD) and Average Percentage of Faults Detected (APFD) are commonly used fault detection metrics. As a result, the proposed study improves the APFD metric by 30% and the TTFFD metric by 70% in high complexity codebases. In contrast, prioritization does not seem to positively affect low complexity codebases according to the experimental results. Considering that safety-critical software ought to be complex, the proposed MC/DC prioritization framework has a practical benefit to ease the burden on the developers.