Have you ever wanted to test against VMware vCenter, but didn't have a lab environment available? How about in an automated fashion, every time you commit new code?
VMware's Go SDK govmomi includes govcsim, a vCenter simulator that mocks APIs.
In my first blog post on this topic, vCenter Simulator Docker Container, I wrote about a VCSIM Docker container that allows an even more portable option.
A follow-up blog post, vCenter Simulator CI Pipeline, explains this repository in detail.
This walkthrough uses PowerCLI and Azure Pipelines, but you could apply these concepts to any vSphere code (e.g. pyvmomi/govmomi) and any CI pipeline provider (e.g. GitLab/AppVeyor).