ie. users with read, readWrite, and custom role with find / insert / update / delete actions allowed for a certain namespace. The app might behave a bit different in some cases ie. what happens if you try and create/drop a database, collection or index? What happens to the sidebar, databases, collection and index lists?

As a basic smoke level of coverage it might be enough to check that namespaces with said roles applied are visible in Compass UI and can be opened (collection workspace opens without errors)