From 1aabcdd4704f2fbe6d9284f368f6cba2ad2e8a4a Mon Sep 17 00:00:00 2001
From: cinereal <cinereal@riseup.net>
Date: Tue, 5 May 2026 11:02:25 +0200
Subject: [PATCH] modular-services: simple example using `mpd`

Signed-off-by: cinereal <cinereal@riseup.net>
---
 docs/manual/usage/modular-services.md       | 18 +++++-------------
 tests/modules/services-modular/basic.nix    |  8 +++-----
 tests/modules/services-modular/demo.service |  8 ++++++++
 3 files changed, 16 insertions(+), 18 deletions(-)
 create mode 100644 tests/modules/services-modular/demo.service

diff --git a/docs/manual/usage/modular-services.md b/docs/manual/usage/modular-services.md
index 102ca5205..943f26307 100644
--- a/docs/manual/usage/modular-services.md
+++ b/docs/manual/usage/modular-services.md
@@ -9,26 +9,18 @@ systemd module loaded into it, so service modules shipped with packages
 (e.g. `pkgs.<name>.passthru.services.default`) drop in unchanged --
 the same module evaluates on NixOS and on Home Manager.
 
-A minimal example -- run a one-shot user service from a package's
-modular service definition:
+A minimal example -- run mpd as a user service:
 
 ```nix
 { pkgs, ... }: {
-  home.services.tunnel = {
-    imports = [ pkgs.ghostunnel.passthru.services.default ];
-    ghostunnel = {
-      listen = "127.0.0.1:8443";
-      target = "127.0.0.1:8080";
-      cert = "/run/secrets/cert.pem";
-      key = "/run/secrets/key.pem";
-      allowAll = true;
-    };
+  home.services.mpd = {
+    process.argv = [ "${pkgs.mpd}/bin/mpd" "--no-daemon" ];
   };
 }
 ```
 
-This produces `~/.config/systemd/user/tunnel.service` with the expected
-`ExecStart`, `LoadCredential`, and `WantedBy=default.target`.
+This produces `~/.config/systemd/user/mpd.service` with `ExecStart` set
+to the mpd binary and `WantedBy=default.target`.
 
 Each service exposes the upstream NixOS-style schema: [`process.argv`],
 `systemd.lib`, `systemd.mainExecStart`, `systemd.service`,
diff --git a/tests/modules/services-modular/basic.nix b/tests/modules/services-modular/basic.nix
index b79f7afc0..3f309130a 100644
--- a/tests/modules/services-modular/basic.nix
+++ b/tests/modules/services-modular/basic.nix
@@ -2,14 +2,12 @@
 {
   home.services.demo = {
     process.argv = [
-      "${pkgs.coreutils}/bin/echo"
-      "hello"
+      "${pkgs.mpd}/bin/mpd"
+      "--no-daemon"
     ];
   };
 
   nmt.script = ''
-    assertFileExists home-files/.config/systemd/user/demo.service
-    assertFileContains home-files/.config/systemd/user/demo.service '/bin/echo'
-    assertFileContains home-files/.config/systemd/user/demo.service 'WantedBy=default.target'
+    assertFileContent home-files/.config/systemd/user/demo.service ${./demo.service}
   '';
 }
diff --git a/tests/modules/services-modular/demo.service b/tests/modules/services-modular/demo.service
new file mode 100644
index 000000000..840611075
--- /dev/null
+++ b/tests/modules/services-modular/demo.service
@@ -0,0 +1,8 @@
+[Install]
+WantedBy=default.target
+
+[Service]
+ExecStart="@mpd@/bin/mpd" "--no-daemon"
+Restart=always
+RestartSec=5
+Type=simple