In which scenarios servername would be null/undefined?

servername is not null or undefined. But the servername is otherwise an IP address. Which gives the warning: DeprecationWarning: Setting the TLS ServerName to an IP address is not permitted by RFC 6066

The warning is still there

https://github.com/TooTallNate/node-socks-proxy-agent/runs/2932280799#step:7:10

Okay, I'll keep looking. But with this change my code runs again.

for the test its i did it like TooTallNate/node-proxy-agent@cd18ccf

should split it in to PRs?

yea, split it into two tests, please!

Okay now I know what happens. Without opts.host the IP address is used and then when I try to connect HTTPS an openssl error occurs and the program crashes. Because of the crash also appears the warning DEP0123