service_runner: add grouping feature

checks/flake-module.nix

@@ -86,6 +86,7 @@ in
 
             # Container Tests
             nixos-test-container = self.clanLib.test.containerTest ./container nixosTestArgs;
+            nixos-systemd-abstraction = self.clanLib.test.containerTest ./systemd-abstraction nixosTestArgs;
             nixos-test-user-firewall-iptables = self.clanLib.test.containerTest ./user-firewall/iptables.nix nixosTestArgs;
             nixos-test-user-firewall-nftables = self.clanLib.test.containerTest ./user-firewall/nftables.nix nixosTestArgs;
             nixos-test-extra-python-packages = self.clanLib.test.containerTest ./test-extra-python-packages nixosTestArgs;

checks/systemd-abstraction/default.nix

@@ -0,0 +1,67 @@
+{ self, pkgs, ... }:
+
+let
+
+  cli = self.packages.${pkgs.hostPlatform.system}.clan-cli-full;
+in
+{
+  name = "systemd-abstraction";
+
+  nodes = {
+    peer1 = {
+
+      users.users.text-user = {
+        isNormalUser = true;
+        linger = true;
+        uid = 1000;
+        extraGroups = [ "systemd-journal" ];
+      };
+
+      # Set environment variables for user systemd
+      environment.extraInit = ''
+        if [ "$(id -u)" = "1000" ]; then
+          export XDG_RUNTIME_DIR="/run/user/1000"
+          export DBUS_SESSION_BUS_ADDRESS="unix:path=/run/user/1000/bus"
+        fi
+      '';
+
+      # Enable PAM for user systemd sessions
+      security.pam.services.systemd-user = {
+        startSession = true;
+        # Workaround for containers - use pam_permit to avoid helper binary issues
+        text = pkgs.lib.mkForce ''
+          account required pam_permit.so
+          session required pam_permit.so
+          session required pam_env.so conffile=/etc/pam/environment readenv=0
+          session required ${pkgs.systemd}/lib/security/pam_systemd.so
+        '';
+      };
+
+      environment.systemPackages = [
+        cli
+        (cli.pythonRuntime.withPackages (
+          ps: with ps; [
+            pytest
+            pytest-xdist
+          ]
+        ))
+      ];
+    };
+  };
+
+  testScript =
+    { ... }:
+    ''
+      start_all()
+
+      peer1.wait_for_unit("multi-user.target")
+      peer1.wait_for_unit("user@1000.service")
+
+      # Fix user journal permissions so text-user can read their own logs
+      peer1.succeed("chown text-user:systemd-journal /var/log/journal/*/user-1000.journal*")
+      peer1.succeed("chmod 640 /var/log/journal/*/user-1000.journal*")
+
+      # Run tests as text-user (environment variables are set automatically)
+      peer1.succeed("su - text-user -c 'pytest -s -n0 ${cli}/${cli.pythonRuntime.sitePackages}/clan_lib/service_runner'")
+    '';
+}