org + env + content_view + name is a valid combination. I can add that to the test.

If a user doesn't specify an environment though (env is optional), there's some complex logic already in the system to fill environment in. It takes things into consideration like does the org have just one non-library environment, what's the user's default environment, etc. Moreover, there's validation that will prevent the user from registering a system to an environment that doesn't contain content_view.