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

Poorly defined requirements are a leading cause of defects and project failure. According to the ISTQB CTFL Acceptance Testing Syllabus and IQBBA FL Syllabus, the quality of requirements plays a critical role in successful solution development and acceptance testing. Requirements must be clear, unambiguous, complete, and testable. When they are vague or ambiguous, stakeholders may interpret them differently, which can lead to incorrect implementations, inadequate testing, and ultimately rework or rejection during acceptance.

Option A is explicitly supported by the ISTQB Foundation Syllabus and IQBBA principles. In contrast:

Option B is incorrect because Agile lifecycles still place great emphasis on requirement engineering, even though requirements evolve iteratively.

Option C misrepresents INVEST: it is a guideline for writing good user stories but does not replace reviews or validation techniques.

Option D is risky and not endorsed by ISTQB. While testers may identify ambiguities, the correct approach is to clarify them with all relevant stakeholders, not make assumptions.

Exact Reference – ISTQB CTFL Acceptance Testing Syllabus (Section 1.3.1):

“Ambiguous, incomplete, or inconsistent requirements increase the risk of misunderstanding between stakeholders, leading to incorrect implementation and ineffective tests.”

Equivalence Partitioning (EP) is a black-box test design technique that divides input data into valid and invalid partitions, where each partition is expected to exhibit similar behavior. In the context of acceptance testing, EP is especially effective because it helps validate whether a system behaves correctly for representative input ranges defined in the acceptance criteria.

Acceptance testing aims to confirm that the system meets business requirements and handles inputs as expected. EP allows the tester to cover a large input space using fewer test cases while maintaining a high level of effectiveness. It supports efficiency, broad coverage, and relevance to user expectations.

Other options are less suitable:

A. Static code analysis is a white-box technique, more relevant to unit or integration testing.

B. Input validation is an objective or activity, not a test design technique.

D. Defect-based testing is more diagnostic, used after failures or during exploratory testing — less structured for planned acceptance testing.

Exact Reference – ISTQB CTFL Acceptance Testing Syllabus (Section 2.4):

“Black-box techniques such as equivalence partitioning and boundary value analysis are suitable for deriving acceptance tests from user stories or business rules.”

Let’s analyze the DMN table shown in the image:

Rule 1: If weight ≤15, size ≤50, and distance ≤10 → use Normal bicycle

Rule 2: If weight is between 15 and 60 kg, size ≤150, and distance ≤25 → use Electric cargo bike

Rule 3: Otherwise → use Electric van

Now consider the options:

A: Incorrect — parcel size is not the only determining factor for using electric vans; it's about weight, size, and distance combined.

B: Incorrect — normal bicycles are used only when weight ≤15 kg, size ≤50 cm, and distance ≤10 km — so not just “short trips.”

C: Incorrect — electric cargo bikes are explicitly used for short trips (≤25 km), per Rule 2.

D: Correct — based on the rules, any weight above 15 kg (and up to 60 kg) results in the use of electric cargo bikes. So if weight >50 kg (but ≤60), cargo bike is still used under the conditions of Rule 2.

Therefore, the most consistent interpretation of the decision model is:

Answer: D. When the weight of the parcel exceeds 50kg then the electric cargo bike is necessarily used