right now the support from different tools for TestNG is almost as good as for JUnit. "Almost", because it still happens that some tools/frameworks first come with JUnit support and then with TestNG. However, the situation has improved much during few last years, and all big players (Eclipse, IntelliJ, Maven, Ant or Spring) and almost all new frameworks (e.g. Arquillan, Gradle) provide support for TestNG out-of-the-box.
Do you have any specific tools (IDEs, frameworks) on your mind?
As for the differences between JUnit and TestNG please see this forum thread.
Book author: Practical Unit Testing with TestNG and Mockito
Joined: Feb 08, 2011
What about Intellij (for development) and Jenkins & Maven (for CI) ?
AFAIK Jenkins does not care (maybe some specific plugins do?), and as for Maven, its testing plugin - surefire - provides decent TestNG support.
IntelliJ supports TestNG out-of-the-box since ages, however I have to warn you that there is some issues with using the latest TestNG with Intellij. As far as I know:
* it can be fixed with some copying of JARs,
* no problems for versions <= 6.3.1
Joined: Feb 08, 2011
But in what aspects is TestNG better than for example JUnit 4.10 ?
Don't get me wrong, I'm no JUnit-addict. I'm just using the tool that looks the most adequate to me. If TestNG does better, then TestNG it is.
regarding JUnit-TestNG differences, have you seen the other discussion I suggested? You will find some information there, please visit this forum thread. I think it would be good if we kept this thread for tooling support.
Billy Tsai wrote:How easy is it to introduce either TestNG or Mockito into a very large legacy codebase?
I really can't answer this question. First of all, I'm not sure what you mean by "introducing", second, adding new technology to your development environment depends very much on the quality of your code, software development process and devs skills!
Billy Tsai wrote:are there examples in the book to mix TestNG, Mockito with other frameworks such as JDummy and JMock? how can we utilize TestNG and Mockito with old test frameworks?
You can think of TestNG as a replacement for other testing frameworks (i.e. JUnit) and of Mockito as a replacement for other mocking frameworks (jMock, EasyMock). If you wish you could use TestNG with any other mocking framework, and you could use Mockito with any other testing framework. However, in the book I concentrate on working with TestNG and Mockito, because I believe that currently they are the most powerful and robust of all existing solutions.