Let's say you have to integrate with several providers by providing them an endpoint the receives json from them and must return json. The json structures each provider gives you and expect back are pretty different even though the essence of the operation is always sort of the same, though each platform has its quirks. I attempt to smooth over some of the differences, and build out my functionality on a common internally use data structure. In these situations, do you bother spec'ing the structures given/expected by each provider? Or the internal common structure only? Or both? Originally I thought I could get away with focusing on only my internal structure, but I'm finding the platforms are different enough in complicated ways that I really want specs for each one. My usage of spec here is to aid in writing tests (not necessarily generative ones)