Ask HN: How do you handle Kubernetes for testing?

I recently worked on integrating Kubernetes in a testing pipeline which included spinning up a cluster for each run. Doing this one either has to spin up an external cluster in the cloud which is slow and costly or create a local cluster. We went with the local option but that brought other drawbacks, such as trouble debugging as the cluster isn't persistent. How do you handle Kubernetes in your testing pipeline?

I've been experimenting with a service for quickly spinning up external clusters (within seconds) that can be kept running as long as needed, in an affordable way. I'm thinking this could also be used to set up staging environments, one for each PR for example. Is there any need for such a service?