This document discusses the importance of testing infrastructure as code. It provides examples of organizations with and without infrastructure as code (IAC) to show the benefits of IAC. These benefits include faster deployment times, increased agility, higher quality, and less downtime. The document outlines different aspects of infrastructure that should be tested, including servers, services, networks, databases, deployments, hybrid environments, access control, and monitoring. It presents an ideal test pyramid with more unit and integration tests than acceptance tests. The goal is to shift infrastructure testing left to catch errors earlier. Overall, the document argues that testing infrastructure as code leads to more reliable deployments and better organizational performance.