Pact Foundation

I'm not clear how I should return a BAD_REQUEST response using state. Do you have example to share?

I think you should put the provider application in such a state so that your productive code is reacting with 400

Pretty much yeah. A useful example would depend on where you cut your provider for verification.

At a high level, your state handler is meant to affect what the provider responds with.

In my architectures, I usually let the presentation &amp; use case layers run normally (to exercise just enough of the application code), and the state handler stubs the input for use cases.