Ensuring your Kubernetes component, such as a controller or an operator, works correctly is an important step before merging a pull request or deploying it to the production. You want to be sure that incoming changes will not introduce any regression or negatively affect any part of the system. This is usually done by running integration and end-to-end tests in the CI/CD pipeline. They test the component on all incoming changes, automatically and in a clean environment, and thereby prevent potential errors and flakes.
However, integration and E2E tests assume there is a working Kubernetes cluster. While there are many tools for running Kubernetes (such as kubeadm or tools based-on kubeadm) many developers experience a lot of problems trying to get Kubernetes running in the CI environment. The CI environments are usually as minimal as possible, while Kubernetes has many dependencies. Installing all the needed dependencies can take a lot of time and sometimes it’s not even possible.