_However, it would be nice to have a test environment on a server for device testing.__> _
I would make a copy of your release server or setup a VM on my home network and get some ip addresses from my isp to link with my test domain name.
What do you think is the best way to set this up? …I was thinking about a sub domain that isn’t indexed and requires login. What are your thoughts?>
Yes, I login is a good idea and If you have test domain name like for example: example.co.uk. You can create a test environment where you know someone will not go on one of your dev site by typing in the wrong url.