Test Analysis and Design

Guided briefing

Test Analysis and Design video walkthrough

A guided overview of chapter 4, connecting the exam language to practical testing decisions.

Briefing focus

Three families of test-design techniques

This is a structured lesson briefing. Real video/audio can be added later as a media source.

Estimated time

8 min

1. 1Three families of test-design techniques
2. 2Black-box: Equivalence Partitioning (EP)
3. 3Black-box: Boundary Value Analysis (BVA)
4. 4Black-box: Decision Tables

Transcript brief

Learn the black-box, white-box and experience-based techniques that turn fuzzy requirements into a focused, risk-driven test suite. The walkthrough introduces the core concept, works through a realistic project example, and closes with the mistakes learners most often make in quiz and exam questions.

Key takeaways

• Recognise the exam wording for this chapter.
• Apply the concept to a real software delivery situation.
• Know which detail to check first when a scenario question feels ambiguous.

Three families of test-design techniques

• Black-box — derive tests from the specification, treating the code as opaque.
• White-box (structural) — derive tests from code structure; measure coverage.
• Experience-based — leverage tester intuition, defect taxonomies and exploratory sessions.

Black-box: Equivalence Partitioning (EP)

Divide each input domain into partitions where the system is expected to behave identically. Choose one representative value per partition.

Black-box: Boundary Value Analysis (BVA)

Defects cluster at edges. BVA tests values at — and just outside — each partition boundary. ISTQB defines 2-value BVA (boundary + just outside) and 3-value BVA (just below, on, just above).

Black-box: Decision Tables

Decision tables model combinations of conditions and their actions. They force testers to enumerate every logical rule — ideal for policy-rich domains like insurance, eligibility or discount engines.

Black-box: State Transition Testing

Model systems as finite state machines. Perfect for workflows like authentication, order status, or vending-machine logic. Test valid transitions, invalid transitions and guard conditions.

White-box techniques

Statement coverage

% of executable statements run by the test suite. Weakest criterion — useful as a minimum baseline.

Branch (decision) coverage

% of branches (True/False outcomes of each decision) executed. 100% branch coverage subsumes 100% statement coverage.

function fareForAge(age: number): number {
  if (age < 16) return 5;   // branch A
  if (age >= 65) return 8;  // branch B
  return 12;                // branch C
}
// tests: fareForAge(10) covers A, fareForAge(30) covers C,
// fareForAge(70) covers B → 100% branch coverage with 3 cases.

Experience-based techniques

• Error guessing — anticipate defects using past experience and defect taxonomies.
• Exploratory testing — simultaneous learning, design and execution, time-boxed and scoped via test charters.
• Checklist-based testing — use curated heuristics (e.g., HICCUPPSF-F, OWASP Top-10) to drive coverage.