I'm currently looking at building an API test automation framework for a series of Rest Services, utilising c#. Coming from a UI-automation background I was after some advise on assertions when testing against an API.
Obviously there are a whole array of different assertions that can be carried out but based on peoples experiences are there certain assertions that must be done? e.g. that the Expected Status Code is returned? Or is this something that can only be ascertained once the API definitions are in place?