mpd: add NixOS tests

This change adds NixOS tests for the MPD (Music Player Daemon) module.
Tests include:

- Playing audio locally using ALSA directly.
- Playing audio locally using PulseAudio (backed by ALSA).
- Playing audio from an external client.
- Rejecting an external client when it's not explicitly allowed (default configuration).

refs #41772

1 files changed, 1 insertions, 0 deletions

diff --git a/nixos/release.nix b/nixos/release.nix
index 0fa8b22cc898..639873cf6d01 100644
--- a/nixos/release.nix
+++ b/nixos/release.nix
@@ -338,6 +338,7 @@ in rec {
   tests.mesos = callTest tests/mesos.nix {};
   tests.misc = callTest tests/misc.nix {};
   tests.mongodb = callTest tests/mongodb.nix {};
+  tests.mpd = callTest tests/mpd.nix {};
   tests.mumble = callTest tests/mumble.nix {};
   tests.munin = callTest tests/munin.nix {};
   tests.mutableUsers = callTest tests/mutable-users.nix {};