API checks from a description

Reads an OpenAPI description as JSON or YAML, lists operations, parameters and responses, and then builds a set of checks: a valid request, wrong types, values outside limits, missing required properties, an unknown path and a missing body. It also checks the provider answer itself: whether the status is declared, whether a content-type header is present, and whether the body matches the schema by type, required fields, enums, limits, patterns and date format. Defects in the description itself are reported too.