Section 1.2. The Value of Fit Tables

1.2. The Value of Fit Tables

Fit tables help solve three major problems in software development:

1. Communication: providing a way for people who want a system to discuss and communicate that need in a concrete way. Too often, developed software is unsuited for its purpose because our understanding of what is needed and what is possible has remained vague and has not been able to evolve, owing to a lack of feedback.

   Written requirements alone are inadequate, especially when they have to be completed without feedback from the development process. Guesses often have to be made about what is important for the future, and many opportunities for gaining business value are not realized.

   It is easy to have misunderstandings with written requirements, leading to the wrong software being built. Having concrete tests that are based on realistic examples from the business domain help build a common understanding of the business needs.

2. Agility: keeping the software in good shape by supporting design changes that are essential as the needs of the business change. Automated tests help define those changes and help ensure that any changes to the software do not break previously satisfied requirements.

   As we'll see in Chapter 17, Fit tests can also help focus the development process, with a major aim of providing the most useful feedback as early as possible to enable businesspeople to guide the development in the best direction, according to their latest understanding of the problem and the solution.

3. Balance: spending less time on gaining balance with fixing problems by reducing the number and severity of problems, catching them early, and making sure they don't return.

   As we'll see in Part II, Fit tests can be introduced in small, focused steps for an existing software product that has lost balance but that needs to support change. Gaining and retaining balance is the key to agility: the ability to respond quickly to business or organizational change.