Could you provide more information on how to use the Diff tool. I would like to compare the response from a message responder with the response from the corresponding live service. What's the best way to set that up?
A Diff tool is typically chained to the response traffic of a Client tool. In this case perhaps a REST Client would be setup to send a message to a virtual service and the Diff tool would be chained to the response traffic and its input would be the actual data from the live service that is should match.
A more complicated case would be to have two client tools and use data banks/variables to store both responses and configure a Diff Tool that is not chained with the responder's traffic as the input and the live service's traffic as the regression control.