How do you test a custom plug-in when you only have Appian Cloud?

We build plug-ins with Plug-in Composer in IntelliJ IDEA, smart services, functions, components, but deploying the JAR to a Cloud environment needs an approval, so there is no quick way to test. For anyone without an on-prem or local setup, what is the best approach to properly test a plug-in before that approval, and what do you use as evidence, screenshots, a video, something else?