Which of the following requirements is testable?
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The system shall be user friendly.
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The safety-critical parts of the system shall contain 0 faults.
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The response time shall be less than one second for the specified design load.
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The system shall be built to be portable.
C is correct because it specifies a measurable criterion (response time < 1 second) under defined conditions (specified design load), making it verifiable through testing. A is untestable because 'user friendly' is subjective without quantified metrics. B is untestable because proving zero faults is impossible - you can only demonstrate the absence of known faults. D is untestable because 'portable' is not defined with specific platforms or measurable criteria.
To answer this question, we need to understand what makes a requirement testable. A testable requirement is one that can be objectively verified or validated. Let's go through each option to understand why it is correct or incorrect:
Option A) The system shall be user friendly - This option is not testable. "User-friendly" is a subjective term and can mean different things to different people. It is difficult to objectively verify or validate if a system is user-friendly.
Option B) The safety-critical parts of the system shall contain 0 faults - This option is not testable. While it is desirable for safety-critical parts to have zero faults, it is impossible to prove that there are absolutely no faults in a system. Testing can help identify and mitigate faults, but it cannot guarantee zero faults.
Option C) The response time shall be less than one second for the specified design load - This option is testable. The requirement specifies a measurable and objective criterion (response time less than one second) that can be validated through testing. The system can be tested to see if it meets this requirement.
Option D) The system shall be built to be portable - This option is not testable. "Portable" is a vague term and can have different interpretations. It is difficult to objectively verify or validate if a system is built to be portable.
The correct answer is C) The response time shall be less than one second for the specified design load. This option is testable because it specifies a measurable and objective criterion that can be validated through testing.