Hello, this is more about Contract testing overall. We have a pair of services that work together: an Ingress service (proxy), which provides authorization, and then an implementation service that does the actual work. Any client will simply call the Ingress service, which will authorize the caller, then pass the request along to the implementation service.
From a contract testing standpoint, the general rule would be to define contracts between the outside consumer and ingress, and then between ingress and implementation. But practically, that doesn't really make sense. My general idea would be to treat the two services as effectively one service, but then I'm not sure how to set that up for proper testing. But one problem at a time. 🙂