Safety-Related Systems CTAL-TTA Practice Questions (Page 6)

Questions 26–30

1. 26application · medium

   A company produces a mobile app that tracks user fitness data. The app has no safety function, but a failure could display incorrect calorie counts. According to the definition of a safety-related system, how should the test team classify this app?

   • AAs a non-safety-related system, because incorrect calorie counts do not pose a risk of death, injury, or environmental damage.
   • BAs a safety-related system, because any software failure is a safety concern.
   • CAs a safety-related system, because incorrect data could lead to user frustration.
   • DAs a safety-related system, because the app is used by the public.
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2. 27foundation · medium

   What is the primary purpose of a Safety Integrity Level (SIL) in safety-related systems?

   • ATo determine the hardware platform on which the software must run.
   • BTo specify the level of risk reduction required for a safety function, which influences the rigor of testing.
   • CTo classify the programming language used to implement the safety function.
   • DTo indicate the maximum number of test cases that must be executed for a given system.
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4. 28foundation · medium

   Why is achieving high coverage criteria like MC/DC important for safety-critical code?

   • AIt guarantees that the code is free of all defects.
   • BIt reduces the need for other testing techniques.
   • CIt ensures that the code is optimized for performance.
   • DIt provides strong evidence that the logic is correct and reduces the risk of undetected faults.
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5. 29application · medium

   A company develops an automotive braking controller classified as ASIL D under ISO 26262. The project manager proposes using statement coverage as the primary white-box criterion to reduce test effort. As the Technical Test Analyst, what is the most appropriate response?

   • ARequire modified condition/decision coverage (MC/DC) as the minimum structural coverage criterion for ASIL D.
   • BUse branch coverage instead, as it is equivalent to MC/DC but easier to achieve.
   • CAccept statement coverage because ASIL D only requires functional testing, not structural coverage.
   • DDefer coverage decisions until after system-level testing is complete.
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6. 30application · medium

   A team is testing a SIL 2 safety function with a simple decision: if (A && B) then shutdown. The team has achieved 100% branch coverage. The safety auditor asks for additional evidence. What is the most appropriate next step?

   • AExplain that branch coverage is sufficient for SIL 2 and no additional testing is needed.
   • BAdd more test cases to achieve MC/DC coverage, even though it is not required for SIL 2.
   • CPerform mutation testing to verify the test cases can detect faults.
   • DReview the test cases to ensure they exercise both true and false outcomes of the decision, and document the coverage achieved.
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