As the first book on the subject of TestNG, Next Generation Java Testing is properly authored by real experts on the framework: the original developer (Cédric) and a major contributor (Hani). They cover a wide range of topics, some only peripherally having to do with TestNG, but all relevant to the issue of testing and to the real-life experience of the authors, much of which is clearly hard-won. Along the way they discuss ways to design code to make it more testable, common coding errors that result not only in ineffective tests but in confusing and hard-to-track errors in production, and particular problems that arise when testing enterprise applications, especially applications that depend upon Java EE container support.
Read David's full review.