ISTQB Exam CTAL-TTA Topic 3 Question 35 Discussion

Context of the Problem:

The software component handles sensor management.

It is used in manufacturing processes that work at SIL 2 and avionics systems.

Failure could lead to a 'major' incident.

The code contains decisions with multiple conditions and no loops.

Safety Integrity Level (SIL) 2:

SIL 2 indicates that the software must adhere to stringent safety standards.

Avionics systems also require high safety standards due to the potential consequences of failure.

Testing Options:

MC/DC (Modified Condition/Decision Coverage):

MC/DC is essential for high-integrity and safety-critical systems like avionics.

Ensures each condition in a decision has been shown to independently affect the outcome.

Required by standards such as DO-178C for avionics software at certain levels.

API Coverage:

Focuses on testing the interfaces between components.

Important but not sufficient alone for high-integrity, safety-critical systems.

Decision Coverage:

Ensures that each decision point (i.e., if statements) is evaluated as both true and false.

Less comprehensive than MC/DC for safety-critical applications.

Statement Coverage:

Ensures that each statement in the code has been executed at least once.

Basic level of coverage, insufficient for safety-critical systems like those at SIL 2.

Best Option:

Given the high safety requirements (SIL 2, major incident potential), MC/DC coverage is the best option. It provides a thorough level of testing needed to meet safety standards.