title: Debugging JUnit Internals
body: <p>I'm wanting to dive into the internals of JUnit so that I can work towards creating a <a href="https://jira.springsource.org/browse/SPR-5292" rel="nofollow">custom runner</a>.  I've attached the source to the JUnit within eclipse, but it seems that it's a slightly different build.  How do I go about "adding" a plugin for JUnit within eclipse which will sync up with the version of attached source that I have?  Is it as simple as creating a folder in the plugins directory, dropping in the jar file and restarting eclipse, then modifying the target runtime?</p>