When you write serverless applications, you use services that live primarily in the cloud.

The AWS shared responsibility model states that AWS is responsible for the security OF the cloud and you are responsible for security IN in the cloud. Similarly, AWS is responsible for the quality OF its services and you are responsible for the quality of the application that you write IN the services.

For example, you shouldn’t need to write tests to verify that Amazon DynamoDB is operating as documented. But you should write tests to verify that you have written your DynamoDB queries to return properly the data you are expecting.