Code Coverage for Safety-Critical Programs Metrics and Considerations

This white paper presents an analysis of code coverage for safety-critical programs, detailing the implications and requirements mandated by four major safety standards. It begins by defining safety-critical systems and the importance of software quality assurance in these contexts. The document outlines the specific code coverage requirements that each safety standard imposes, including ISO 26262, IEC 61508, DO-178C, and EN 50128. It explains that code coverage is a method for measuring the percentage of source code that has been executed during testing, which is crucial for identifying untested areas of a program. The paper further discusses various coverage metrics, such as function coverage, line coverage, statement coverage, decision coverage, Modified Condition/Decision Coverage (MC/DC), and Multiple Condition Coverage (MCC). Each metric is defined, and its relevance to safety standards is examined, emphasizing the necessity for achieving specific levels of code coverage to ensure software reliability and safety in regulated industries.