When developing plugins for MCollective testing can be a pain since true testing would mean you need a lot of virtual machines and so forth.
I wrote something called the MCollective Collective Builder that assist in starting up a Stomp server and any number of mcollectived processes on one machine which would let you develop and test the parallel model without needing many machines.
I’ve found it to be very useful in developing plugins, I recently wrote a new encrypting security plugin and the entire development was done over 10 nodes all on a single 512MB RAM single CPU virtual machine with no complex plugin synchronization issues etc.
You can see how to use it below, as usual it’s best to view the video full screen.