Defect Lifecycle

This topic covers managing defects. You follow a bug through its lifecycle states, distinguish severity from priority, apply root-cause analysis to prevent recurrence, and compute quality metrics such as defect removal efficiency and leakage.

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.

A defect moves through a well-defined lifecycle so its status is always clear — from newly reported, through assignment and fixing, to verification that the fix works and finally closure. Two independent attributes drive handling: severity is the technical impact (a crash is high severity) while priority is business urgency (a cosmetic bug on the home page may be high priority), and the two need not agree. After a fix, regression testing confirms nothing else broke. At the process level, defect removal efficiency — the fraction of defects caught before release — measures how effective the quality process is, and root-cause analysis turns individual bugs into systemic improvements that stop whole classes of defects recurring.

State assumptions explicitly before using any relation for defect lifecycle — 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 defect lifecycle.
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.

Defect Lifecycle 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 defect lifecycle with earlier units — revise prerequisites before attempting mixed problems.

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

Students conflate severity with priority (they are distinct axes), skip regression testing after a fix, and confuse defect removal efficiency with defect density. Closing a defect without verification, or without root-cause analysis, lets the same bug return.

Before attempting defect lifecycle problems, confirm you can:

1. Lifecycle: New → Assigned → Fixed → Verified → Closed
2. Root-cause analysis prevents recurrence
3. Run regression tests after every fix

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