Could you give the motivation for wanting to remove Junit from the bundle?

It's nice that the Gradle distro is easy to install & fairly self-contained.
If the goal is to avoid hijacking someone's own version of junit, could
the same end be achieved using a classloader hierarchy
(similar to how Tomcat does it)?

The user's have to specify junit anyway in there classpath to make their build work. Then we have an additional junit version bundled with Gradle to be used by the Ant junit-runner. Due to Tom Eyckmans refactoring of the test tasks, we will get rid of the ant junit runner anyway soon (and then we don't need to ship junit with Gradle).

Should also remove the testng jar from the distribution, for the same reasons.

We need this jar present when the build uses junit 3 or an early version of junit 4, as the jar adds some additional stuff that the test runner uses.