Groovy has excellent support for Unit Testing with JUnit 3.8.2 and Mocking capabilties built right in. Currently, special support doesn't exist for JUnit 4 but its easy to use so long as you are using Groovy 1.1 (currently in beta) and Java 5+ (a requirement for annotations/Junit 4.x). Here is an example.
Make sure you are using Groovy 1.1 (we used beta-2) and JUnit 4.x (we used 4.4).
Our test class includes two tests additionIsWorking and divideByZero. The second of these is expected to fail with an ArithmeticException exception.
Running the test gives:
Suppose we want to test the following program:
Here is what your code might look like. This example uses parameterization.
The output will look something like this: