Book Review: Test-Driven Development By Example

Test Driven Development By Example is a Kent Beck book that introduces developers to the concept of driving feature development through the use of tests. This is not a new book on the subject, but it is the book that all developers should read. I have been developing using tests for quite some time, and I have used TDD techniques as part of my development methodology. Unfortunately it took me until recently to decide and read an actual book on the subject.

Kent uses two different examples to show the steps that take place in a Test Driven solution. The first example is a Money application that uses Java for its solution. The second example is an exercise in building your own xUnit testing framework for Python. These examples show the cadence a developer uses to go from broken test to passing test. Rather then describing theory for how to write tests, Kent demonstrates. While showing the reader what steps are made and why decisions are made, he is actually building a case for specific patterns. The third section of the book looks at specific TDD patterns.

This book does a wonderful job of demonstrating small focused tests. Create a test that fails, make it pass, refactor. Each chapter follows this pattern by focusing on a single task. Many of the chapters are less then five pages. They focus on a single test that needs to be implemented and the following implementation. This style may seem rather annoying at first, but definitely conveys the sense of being able to put down the book at any time. You can in turn pick up the book and quickly get right back into the exercises.

This is a great book for both beginners and experienced TDD developers. Beginners will get a great first lesson on how to TDD and why it can be as successful as it is. Experts can get reinforcement on why decisions and behaviors are important.