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.”
