The Theory & Application of Defect Centric Approach

An effective test strategy is the key to winning over the defects to deliver excellent software quality. Designing a good test strategy is considered to be experience-based and considered to be art. No doubt, experience does play a significant role, but there is a science behind test strategy. Test strategy is about figuring out what types of defects have to be uncovered, when and how. The science to designing a test strategy is based on defect centric approach that critically identifies the potential defect types, its propagation ability, its impact and then arriving at a cost-effective implementation.

Test strategy is not an ad-hoc collection of the various types of tests, techniques and the process of testing. This is not purposeful and does not guarantee quality as we are not clear as to what types of defects we intend to uncover. A defect centric approach on the other hand is very purposeful and goal-focused; its intention is to clearly identify the different types of defects that we need to uncover. Having identified the specific defect types to uncover to meet customer expectations, it is then about figuring out the optimal stage of detection and effective test type and test technique and process model to detect this.

A defect centric approach also forces weeding out ambiguity in the requirements, making them testable, and establishes a base line for evaluating the test quality and product health. This tutorial will help you understand the theory of test strategy formulation – (1) Defect typing (2) Fault propagation model (3) Value prioritization (4) Attribute clarification (5) Value prioritization and (6) Optimal defect staging that form the core of the defect centric approach to test engineering.

The objective of this tutorial is look at the act of test strategy formulation from a scientific perspective to create a winning strategy. The tutorial should aid a test lead/architect/manager to create test strategy using a formal approach that will indeed be effective. At the end of this tutorial you will be confident that the strategy you create will indeed be a winning one.