Pulumi offers a framework for testable Infrastructure as Code, enabling fast local unit testing without cloud dependency, although it initially lacked comprehensive IAM Policy support. The author addresses this by developing a library to manage IAM Policy documents using JSON objects, noting the absence of built-in validation which prolongs the feedback loop when errors occur. Emphasizing the importance of compliance in the financial industry, the author explores various methods for testing and validating IAM Policies, including leveraging Pulumi's aws.iam.getPolicyDocument API and the AWS CDK, despite limitations such as the need for mock functions and the complexity of integrating the entire CDK package. The @thinkinglabs/aws-iam-policy library is introduced as a solution for writing and validating policies as code, significantly reducing syntax errors and improving the feedback cycle. The text concludes by discussing future improvements such as enhanced condition validation and support for additional policy elements, illustrating the benefits of extending Pulumi programs to preemptively address errors and enhance developer guardrails in policy deployment.