AWS CDK is an IaC (Infrastructure as Code) Framework that allows developers to easily create and manage serverless applications by combining various AWS resources such as Lambda, API Gateway, and DynamoDB tables with just a few lines of code. While CDK greatly simplifies the process of building and deploying these types of applications, it is still important to verify that they are functioning as expected. In this talk, we will delve into the different ways of testing CDK apps to ensure their reliability, using a real-world example to illustrate the concepts discussed. This will include a discussion of unit testing Lambda functions, snapshot testing, and fine-grained assertion testing of CDK stacks. We will also explore the importance of integration testing in gaining confidence in your application, and demonstrate how to split an application into smaller, more manageable components that can be deployed and tested individually.