What to test the API for, having its descriptions in the Swagger JSON format?

Question

API

Hello. I'm going to test the API, a number of conceptual questions have gathered.
Given:
- Documentation in swagger.json format
Questions:
- Do I need to validate types (including nested ones)?
- What to do with the required parameters
- Since the scheme is generated by the backend and immediately tested, is it necessary to separate the scheme, that is, to make some scheme of the "expected API" and dance from it, comparing it with the current one?

Answer 1

When testing, the main thing to remember is that anything can come from the client and nothing can be trusted. It is necessary to double-check any incoming data, even if the instructions say that a number is passed in the parameter, then there will be a unique one that will send war and peace as a string in this parameter.