Something I needed for one of my projects and couldn't find, so I made it myself.
https://codeberg.org/SpotlightKid/mock-udp-server
A minimal, threaded UDP server for testing UDP clients in Nim.
Records all received packets with metadata (timestamp, sender address/port, raw data) for unit test assertions.
Very simple but handy.
Comments welcome, but I'll be off-line until Sunday.