How to Test? (Confirmation)

[MsHannerBananer]

I see that included with SOMA there's also a Workshop upload application. Is the only way to go about testing what you already have to publish with Workshop?

I know that map viewer is a thing, but isn't yielding accurate results for my maps. I'm getting weird texture feedback and just have never found it a decent way to test my maps.

I haven't really worked with Workshop before. Is there a way to make what you publish with it private until you want to reveal it to the world? I'd rather not have my map open for people to laugh at. xD