preface to the first edition To date tests are still the best solution mankind has found to deliver working software. This book is the sum of four years of research and practice in the testing field. The practice comes from my IT consulting background, first at Octo Technology and then at Pivolis; the research comes from my involvement with open source development at night and on weekends. Since my early programming days in 1982, I've been interested in writing tools to help developers write better code and develop more quickly. This interest has led me into domains such as software mentoring and quality improvement. These days, I'm set- ting up continuous-build platforms and working on development best practices, both of which require strong suites of tests. The closer these tests are to the coding activity, the faster you get feedback on your code--hence my interest in unit testing, which is so close to coding that it's now as much a part of development as the code that's being written. This background led to my involvement in open source projects related to soft- ware quality: Cactus for unit-testing J2EE components (http:/ /jakarta.apache.org/cactus/) Mock objects for unit-testing any code (http:/ /www.mockobjects.com/) Gump for continuous builds (http:/ /jakarta.apache.org/gump/) Maven for builds and continuous builds (http:/ /maven.apache.org/) The Pattern Testing proof of concept for using Aspect-Oriented Programming ( AOP ) to check architecture and design rules (http:/ /patterntesting.sf.net/) JU nit in Action is the logical conclusion to this involvement. xxi