Ringo De Smet, founder of Cumundi, highlights the company's use of Pulumi for creating reusable infrastructure code libraries, which are essential for helping businesses efficiently adopt cloud infrastructure. Pulumi facilitates rapid iterations through the build-test-release cycle and supports Cumundi's approach of encapsulating non-functional requirements into code libraries, thereby maintaining clean and modular infrastructure across different cloud platforms. The article demonstrates the implementation of Test-Driven Development (TDD) practices in Pulumi, showcasing how ComponentResource and properties like parent and aliases allow for the effective refactoring of infrastructure code. By using Pulumi, Cumundi caters to customer needs by setting up infrastructure and visualizing resource relationships through a state graph on the Pulumi platform, while also addressing challenges like overcoming code duplication and maintaining clear parent-child resource relationships.