This is an open question. I know no answer is wrong or correct. If someone asks this question in an interview He wants to understand your thinking process. Can anyone put a light on this, how to answer this question?
I like to answers questions with questions during interviews. My first response would be that the question "How to test AWS?" is very broad.
My first question would be: Which part of AWS should I test?
As of 2020, AWS comprises more than 175 products and services including computing, storage, networking, database, analytics, application services, deployment, management, mobile, developer tools, and tools for the Internet of Things.
Dear interviewer did you mean to ask "how-to test this application deployed on AWS?" instead.
Maybe you care to explain how your application is deployed to AWS first? Testing is very depended on context, so to truly answer your question I need to understand your context first.
Maybe we can draw the high level architecture on a white-board and I can ask some critical thinking questions and identify some risks.