Test Analysis and Design

Chapter 4 in the CTFL exam

Exam questions

11 / 40

Share of exam

28%

Highest K-level

K3

Glossary terms

101

Chapter 4 carries the heaviest K3 load in the syllabus. You must apply equivalence partitioning, boundary value analysis, decision table testing, state transition testing, and statement and branch coverage to given scenarios — not merely describe them.

What this chapter covers

Chapter 4 is the largest slice of the exam at 11 of 40 questions, and the only chapter where most questions require you to actually apply a technique to supplied data. Time spent working through examples here returns more marks than anywhere else in the syllabus.

Test techniques are grouped into three categories, plus a fourth collaborative grouping. Black-box techniques derive tests from the specification without reference to internal structure. White-box techniques derive them from the implementation. Experience-based techniques draw on the tester's knowledge, skill, and intuition. Collaboration-based approaches focus on preventing defects rather than detecting them.

Equivalence partitioning divides the value domain of a variable into partitions whose members are expected to be processed identically, so one representative value tests the whole partition. Coverage is the proportion of partitions exercised. Boundary value analysis extends this to the edges of ordered partitions, where defects cluster: two-value BVA tests the boundary and its nearest neighbour across the edge; three-value BVA adds the neighbour inside. Note the distinction the exam exploits — an equivalence partition is the subset itself, while equivalence partitioning is the technique that uses it.

Decision table testing captures combinations of conditions and their resulting actions, which makes it the technique of choice when business rules interact. Each column is a rule and a candidate test case. State transition testing models the system as states, events, transitions, and actions; coverage may be measured over all states, all valid transitions (0-switch), or sequences of transitions (N-switch).

White-box techniques measure structural coverage. Statement testing exercises executable statements, with statement coverage the percentage reached. Branch testing exercises the outcomes of decisions, with branch coverage the percentage of branches taken. 100% branch coverage guarantees 100% statement coverage, but not the reverse — a fact the exam tests directly. White-box testing's value is that it measures coverage of what was actually built, catching code the specification never mentioned.

Experience-based techniques cover error guessing (anticipating likely mistakes), exploratory testing (concurrent learning, design, and execution, usually time-boxed in sessions against a test charter), and checklist-based testing. Collaboration-based approaches — collaborative user story writing, acceptance criteria, and acceptance test-driven development — sit in this chapter in v4.0 and are examined as defect-prevention practices.

CTFL v4.0 syllabus outline

1. 4.1 Test Techniques Overview

2. 4.2 Black-box Test Techniques

   • Equivalence Partitioning
   • Boundary Value Analysis
   • Decision Table Testing
   • State Transition Testing

3. 4.3 White-box Test Techniques

   • Statement Testing and Statement Coverage
   • Branch Testing and Branch Coverage
   • The Value of White-box Testing

4. 4.4 Experience-based Test Techniques

   • Error Guessing
   • Exploratory Testing
   • Checklist-Based Testing

5. 4.5 Collaboration-based Test Approaches

   • Collaborative User Story Writing
   • Acceptance Criteria
   • Acceptance Test-driven Development (ATDD)

Highest-value terms in this chapter

Start here if you are short on time.

• equivalence partitioning
• equivalence partition
• boundary value analysis
• decision table testing
• state transition testing
• statement coverage
• branch coverage
• exploratory testing
• error guessing
• acceptance criteria

Common exam traps

• ⚠️Assuming 100% statement coverage implies 100% branch coverage. It is the other way round.
• ⚠️Confusing an equivalence partition (the set of values) with equivalence partitioning (the technique).
• ⚠️Miscounting boundary values — be certain whether the question wants two-value or three-value BVA.
• ⚠️Treating exploratory testing as unstructured. It is time-boxed and charter-driven.
• ⚠️Forgetting that a decision table's rules must be reduced before counting test cases when conditions are irrelevant.