anchor.diff:      play_some_music($serverALSA);
       play_some_music($serverPulseAudio);
   
  +    $client->waitForUnit("multi-user.target");
       $client->succeed("$mpc -h serverALSA status");
   
       # The PulseAudio-based server is configured not to accept external client connections
  
positive.code:     };
  
    nodes =
      { client = 
        { ... }: { };
  
        serverALSA =
          { ... }: (mkServer {
            mpd = defaultMpdCfg // {
              network.listenAddress = "any";
              extraConfig = ''
                audio_output {
                  type "alsa"
                  name "ALSA"
                  mixer_type "null"
                }
              '';
            };
  
            musicService = with defaultMpdCfg; musicService { inherit user group musicDirectory; };
          }) // { networking.firewall.allowedTCPPorts = [ 6600 ]; };
  
        serverPulseAudio =
          { ... }: (mkServer {
            mpd = defaultMpdCfg // {
              extraConfig = ''
                audio_output {
                  type "pulse"
                  name "The Pulse"
                }
              '';
            };
  
            musicService = with defaultCfg; musicService { inherit user group musicDirectory; };
          }) // { hardware.pulseaudio.enable = true; };
      };
  
    testScript = ''
  
negative.code: import ./make-test.nix ({ pkgs, lib, ... }:
    let
      track = pkgs.fetchurl {
        # Sourced from http://freemusicarchive.org/music/Blue_Wave_Theory/Surf_Music_Month_Challenge/Skyhawk_Beach_fade_in
  