Test Case Design Techniques

This topic covers structured techniques for generating tests. You build decision tables for rule-based logic, apply pairwise (combinatorial) testing to reduce case counts, model event behaviour with state-transition diagrams, and ensure coverage via a traceability matrix.

Relation 1 —

Write this relation with symbols exactly as in Kaner Testing — Standard reference before substituting numbers. Examiners award partial marks for a correct setup even when arithmetic slips.

Relation 2 —

Write this relation with symbols exactly as in Kaner Testing — Standard reference before substituting numbers. Examiners award partial marks for a correct setup even when arithmetic slips.

Relation 3 —

Write this relation with symbols exactly as in Kaner Testing — Standard reference before substituting numbers. Examiners award partial marks for a correct setup even when arithmetic slips.

Exhaustive testing is impossible, so these techniques maximise defect-finding per test. A decision table lays out every relevant combination of conditions against the expected action, exposing rules that are missing or contradictory. When many parameters interact, testing all combinations explodes, but most defects involve only two factors, so pairwise testing covers every pair with far fewer cases. State-transition testing suits systems with modes and events, checking that each valid transition works and, importantly, that invalid transitions are rejected. Throughout, a traceability matrix ties tests back to requirements so gaps and redundant tests become visible, and negative cases guard against unexpected inputs.

State assumptions explicitly before using any relation for test case design techniques — steady state, uniform properties, linear elastic material, ideal gas, incompressible flow, etc., as applicable.

Wrong assumptions invalidate the entire solution even when the formula is correct. In Software Testing viva and GATE descriptive questions, listing valid assumptions often earns separate marks.

1. Read the question and list given data with SI units (common in Software Testing papers).
2. Draw a neat labelled diagram where applicable — examiners in Indian universities award diagram marks even when arithmetic slips.
3. Identify which relation from this topic applies to test case design techniques.
4. Use equation 1: .
5. Use equation 2: .
6. Substitute values, compute, and verify units and sign (direction).
7. State conclusion in one line — e.g. safe/unsafe, stable/unstable, feasible/infeasible.

Test Case Design Techniques appears in QA teams and CI pipelines. In Indian it software curricula this topic is tested because it connects theory to verification and validation.

GATE and semester exams often combine test case design techniques with earlier units — revise prerequisites before attempting mixed problems.

Industry interview panels sometimes ask: "Where did you use test case design techniques?" — answer with a lab, mini-project, or plant visit example if possible.

Students test only valid (positive) cases and omit negative ones, try to test all combinations instead of using pairwise reduction, and build incomplete decision tables that miss condition combinations. Ignoring invalid state transitions is a frequent oversight.

Before attempting test case design techniques problems, confirm you can:

1. Include both positive and negative test cases
2. A traceability matrix links requirements to tests
3. Error guessing leverages tester experience

Revise the solved examples in Kaner Testing — Standard reference and one previous-year GATE or university paper for this unit.