Prevent test failure when not expecting response and it is not in JSON format

When not expecting a response in a test, and the response was not in JSON format, a parse error would lead to a test failure.
Added checks for not expected responses in test cases so the response body is not tried to be parsed into JSON for the response check.
It includes collect_response and break_response keys too, and the response is still required by default to have a 200 status code.