It is always interesting to read a book about a technical topic from its creator. They tend to better identify the motivating factors and history that went into creating the product than other authors could possibly try. Kent Beck is the creator of JUnit, and happens to be the author of this book. The book is designed for people who are new to unit testing and Test-Driven Development. For anyone in the current software development industry, this is very few people.
The book is divided into three separate sections. The first being a walk-through with JUnit (by example), xUnit, and then a “best practices guide.” The JUnit section, the majority of the content of this book, is focused on developing a currency class. While there were some interesting design decisions, this part irritated me the most. The first section produced blatant errors, just to create a test that would fail. I would have preferred if these errors had been described rather than presented to the reader. The currency example was a good example, however adding another example would have been better. The xUnit section of the book focused on creating a test environment for Python. I am not a Python developer, but I have written a very small amount of code. I was not a fan of this section. However, I was pleased with the best practices section. The only issue I had with the last section is that I do not recall that the best practices section went into why the recommendations are better than what they replace. If my memory serves me correctly, it did not.
This is a great resource for developers who have never heard of TDD. It may even be a great book for students that have just completed half of a class in Java. However, it is not such a great book for people who have worked with Test Driven Development. For those who have already worked with TDD, a Manning Press’s “In Action” series may be more suitable. Although their resource on JUnit looks to be a bit dated. Manning Press’s dated JUnit book includes information on integrations with other frameworks, which are slightly harder to test against [J2EE, XML, Servlets, EJB, DBs….].
In summary, I was probably looking for another book similar to “Pragmatic Unit Testing in Java with JUnit” (Hunt and Davis). Their approach was more focused on how to try to find trouble spots, and improve existing code.
Given that this was written in 2002, the following is not exactly fair criticism, but it should be mentioned by anyone that is claiming that TDD is beneficial. I would have liked to see more support [research/studies] on why Test Driven Development is beneficial. Every TDD-related article/publication/book that I have read always attempts to convince the reader that it’s necessarily with marketing-speak. The claim is that it is good for “high stress environments,” or it reduces defects. However, I have never seen evidence supporting the claim mentioned. I, personally, have found that TDD to be a significant improvement in development. However, I have never been able to quantify how much of an improvement it has made. What is the amount of time saved by TDD? Has it made today’s software more reliable than before? Has it affected the developer job market? [Increased/Decreased] Has it made the users of the products using TDD happier? Most importantly, has test-driven development reduced the stress of software development?