Test Analysis and Design practice questions

Black-box test techniques are based on an analysis of the specified behavior of the test object, without reference to its internal structure.

The tester's input is the requirements specification, which describes required behavior, and the code is deliberately not consulted. That is a black-box (specification-based) technique. White-box would need the code or design; experience-based would rely on the tester's own knowledge rather than a specification.

1. Identify what the tests are derived from: a requirements specification.
2. Note that the internal structure is not used.
3. Match specified behavior without internal structure to black-box.

Exam tip: Tests from the specification, not the code: black-box.

White-box test techniques are based on an analysis of the test object's internal structure and processing.

Decisions and control flow are part of the internal structure of the code, so test cases derived from them come from a white-box (structure-based) technique. A black-box technique would use the specification; an experience-based technique would use the tester's knowledge of likely failures.

1. Identify the source of the tests: the code's decisions and control flow.
2. Recognise this as internal structure and processing.
3. Map internal structure to white-box.

Exam tip: Tests from the code's structure: white-box.

Test techniques support the tester in test analysis (what to test) and in test design (how to test).

In test analysis the tester identifies test conditions, which is what to test; in test design those conditions are elaborated into test cases, which is how to test. The reversed pair is the tempting near-twin. Planning, implementation, monitoring and execution are real activities but are not the ones the syllabus links to techniques.

1. Recall that analysis produces test conditions: what to test.
2. Recall that design produces test cases: how to test.
3. Check the order in each option.
4. Choose analysis then design.

Exam tip: Analysis = what to test; design = how to test.

Experience-based test techniques use the knowledge and experience of testers, so their effectiveness depends heavily on the tester's skills.

Black-box and white-box techniques give a systematic procedure based on the specification or the code, so different testers tend to derive similar test cases. Experience-based techniques rely on what the tester knows about likely failures, which is why a large difference between two testers is most expected there. Collaboration-based approaches are not a category of test technique at all; they rest on criteria a whole team agrees.

1. Ask which category depends on the person rather than on a systematic derivation.
2. Recall that experience-based effectiveness depends heavily on tester skills.
3. Note that collaboration-based work is an approach, not a technique category.
4. Choose experience-based.

Exam tip: Experience-based results vary with the tester's skill.

Experience-based test techniques can detect defects that may be missed using black-box and white-box techniques, so they complement them.

Black-box and white-box techniques are systematic, but they only find what their test basis and coverage items lead to. Testers' knowledge of typical failures can reveal defects outside that, so the syllabus calls experience-based techniques complementary. They do not replace the others, are not defined by a coverage measure and do not share their test basis.

1. Recall the meaning of complementary: used together, adding something.
2. Recall what experience-based techniques add: defects the others miss.
3. Reject options about replacing techniques or measuring coverage.

Exam tip: Experience-based testing adds defects that systematic techniques miss.

Black-box test cases are independent of how the software is implemented, so they remain useful when the implementation changes but the required behavior stays the same.

Because black-box techniques use only the specified behavior, a rewrite that keeps the behavior leaves those tests valid. White-box tests were derived from the old control flow and structure, so they follow the replaced design; keeping both overlooks that dependence, and redesigning everything ignores that the black-box tests still match the unchanged behavior.

1. Note what changed (the implementation) and what did not (the required behavior).
2. Recall that black-box tests depend only on behavior.
3. Recall that white-box tests depend on the design and code.
4. Choose the specification-based tests.

Exam tip: Implementation changes, behavior stays: black-box tests survive.