Thanks so much! That's really helpful.
Yeah, redirecting would be silly.
I'm still learning how to work within this environment. I didn't know that I could just rename the folders. I have WordPress installed there, so presumably that would still work because it refers to the config files, but the automated / one-click upgrades would no longer work (?), so creating the mirror might be best?
I've tried the mirroring thing, mirroring www.xyz.com to look at test.xyz.com, but when I go to www.xyz.com now, I can see in the browser own the bottom that it's looking for data from test.xyz.com.
Is there any way around that?
Maybe I do just need to do what you suggested, about renaming the files (but I'd prefer the on-click installs to not break).