How to automate testing of participants?

We have recently deployed a set of participants and advisors (server-side) and I am looking for guidance/best practices around automating testing within RTC.  For example, i'd like to write a testcase that opens a new work item (checks a few things), then attempts to move it to a state (via action) but has not entered valid information and it validates that a server-side validator comes back with an error, it gets fixed, the action works, etc.

Susan