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SPIRAL (AGILE) SOFTWARE TESTING METHODOLOGY: PLAN, DO, CHECK, ACT

Spiral development methodologies are a reaction to the traditional waterfall systems development, in which the product evolves in sequential phases. A common problem with the life-cycle development model is that the elapsed time to deliver the product can be excessive, with user involvement only at the very beginning and very end. As a result, the system that they are given is often not what they originally requested.

By contrast, spiral development expedites product delivery. A small but functioning initial system is built and quickly delivered, and then enhanced in a series of iterations. One advantage is that the users receive at least some functionality quickly. Another advantage is that the product can be shaped by iterative feedback; for example, users do not have to define every feature correctly and in full detail at the beginning of the development cycle, but can react to each iteration.

Spiral testing is dynamic and may never be completed in the traditional sense of a delivered system’s completeness. The term spiral refers to the fact that the traditional sequence of analysis–design–code–test phases is performed on a microscale within each spiral or cycle in a short period of time, and then the phases are repeated within each subsequent cycle.

The objectives of this section are to:

1. ■ Discuss the limitations of waterfall development.

2. ■ Describe the complications of client/server.

3. ■ Discuss the psychology of spiral testing.

4. ■ Describe the iterative/spiral development environment.

5. ■ Apply Deming’s continuous quality improvement to a spiral development environment in terms of:

   1. Information gathering

   2. Test planning

   3. Test case design

   4. Test development

   5. Test execution/evaluation

   6. Traceability/coverage matrix

   7. Preparing for the next spiral

   8. System testing

   9. Acceptance testing

   10. Summarizing/reporting spiral test results