Testing Lua locally (multiple gmod instances?)

I’ve been searching for an answer to this for a long time with no luck. Is there any way to test the multiplayer aspects of a script/mod locally with just one steam account? For instance, could I create a listen server and somehow join it as a second player with a second instance of gmod? Or, do you absolutely need at least two steam accounts and a second OS to run two instances simultaneously even when just testing locally?

How do developers test their multiplayer code locally by themselves? The bots are of very little help.

Most people just use bots, they aren’t the smartest but they do help. You can also forward your ports so people can join, then just invite some friends or something. I don’t think it’s possible to run two clients at the same time.

How do I create bots? I do “bot john” and it says “Failed to create bot”

you cxant do bots in single player, you will get the “Failed to create bot”, try multiplayer “Create Multiplayer” always worked for me

Yeah I got it.

Use scrds and invite someone to join. Or use bots.