I try to avoid (if possible) running any server, whether it's test environment or not, non-dedicated, I prefer the most stable environment I know, which is a dedicated server, and it *is* possible to run a dedicated server on the same machine you play on, however, I don't suggest advertising it as a public server for a few reasons, 1 security, 2 you probably don't have the bandwidth for it and people will lag like crazy. Here's a screenshot of a DoD: Source running on my local machine along with it's command line set up.
Dedicated Local Server Screenshot
To run this
All you need is the hldsupdatetool (available free for linux or windows on steampowered.com) and to know 2 command lines to it.
There are also a few instructional videos on how to set up a server like this floating around the web somewhere. You just change a couple things to them to make it work on a "local" environment.
Really, I have, with both Source and HL1 based games have had more crashes, lock ups, freezes, and problems running a listen server than anything else. I personally do not suggest it.
There's other command line options you can use to modify other settings as well, but I'm not gonna go over it.
Alright rant against listen server as a test environment done....
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