CTFL-AcT Exam Dumps : ISTQB Certified Tester - Acceptance Testing (CT-AcT)

ISO/IEC 25010 defines two key quality models:

Product Quality Model (e.g., Usability, Security, Portability)

Quality in Use Model — which includes characteristics of the user’s experience when interacting with the product in a real-world context.

The four main characteristics of the Quality in Use model are:

Effectiveness

Efficiency

Satisfaction

Freedom from risk

Option A — Efficiency is one of the key Quality in Use characteristics, as it refers to the resources used to achieve goals with accuracy and completeness.

Other options:

B (Usability), C (Compatibility), and D (Portability) are characteristics of the Product Quality Model, not of Quality in Use.

Therefore, the correct answer, as per ISO 25010:2011, is:

Answer: A. Efficiency

Clear, complete, and testable requirements or user stories are critical for effective acceptance testing. Ambiguities or vague statements lead to differing interpretations by stakeholders, developers, and testers. This often results in software that doesn’t meet user expectations or in tests that fail to verify business needs correctly.

Option B is correct because it highlights the importance of precise requirements in both implementation and testing phases. Ambiguities can result in incorrect behavior, untestable features, or test cases that don’t align with business goals.

Other options:

A is risky — while testers may explore assumptions during exploratory testing, relying on assumptions rather than clarification increases risk.

C is incorrect — the INVEST mnemonic helps write better user stories, but it doesn’t replace review or validation processes.

D is false — Agile still values requirements engineering; it’s more collaborative and incremental, with the product owner playing a key role, not diminishing its importance.

Answer: B. Vague or ambiguous requirements may lead to misunderstandings both during implementation and testing

The goal here is to achieve full decision coverage (also known as branch coverage), which means each decision point in the process must evaluate to both TRUE and FALSE at least once during testing.

From the BPMN ATM withdrawal model, we identify two key decisions:

Is the balance ≥ $100?

If yes, is receipt = YES?

To achieve full decision coverage:

One test must evaluate decision 1 as TRUE and another as FALSE.

If decision 1 is TRUE, then decision 2 must be exercised both ways (receipt = YES and NO), but for minimal decision coverage, one path through decision 2 is enough.

Analyzing test cases:

Test 1 (balance = $100, receipt = YES): decision 1 = TRUE, decision 2 = TRUE

Test 2 (balance = $99): decision 1 = FALSE

These two tests ensure:

Decision 1 evaluated TRUE (Test 1) and FALSE (Test 2)

Decision 2 evaluated at least once (receipt = YES in Test 1)

Thus, Test 1 and Test 2 form the minimal set for full decision coverage.

Other options:

C and D are redundant for the minimal set.

A includes an extra test not needed for minimal decision coverage.

Answer: B. Test 1, Test 2