I would have thought the best thing to do would be to run two servants on the same computer, or (if you've multiple PC's) run one servant on one and one on another. If you're running on just the one computer then just ensure that you're using different port numbers for each servant, e.g. 6346 for the stable servant and 6347 for the test one.

Granted this won't demonstrate the full message passing and routing, but it would be a good start.

Rachel