If you haven't alerady, go take a look at "Perl Testing, A Developer's Notebook (Langworth & chromatic), particularly the last chapter ("Testing Everything Else"). There are several tools and tricks that can be applied to testing non-Perl code. Basically, you can treat your C++ as a black box, and wrap it in an eval-block. For a given stimulus, you have an expected response, that you can code for (by examining $@, any temporary files that get written, databases modified, etc.) in a Test::More test harness.

If this were me confronted with this project, I'd strongly consider going down the 'Test' path in parallel with the 'Automation' path. There will be enough cross-talk between the two to make this a very useful approach. The Test path will give you the means to determine and report your C++ code in action, which the Automation path can use to make go/stop and fix/nogo decisions.