systemd: name slice unit correctly

modules/systemd.nix

@@ -125,9 +125,9 @@ in {
 
       slices = mkOption {
         default = { };
-        type = unitType "slices";
-        description = unitDescription "slices";
-        example = unitExample "Slices";
+        type = unitType "slice";
+        description = unitDescription "slice";
+        example = unitExample "Slice";
       };
 
       sockets = mkOption {
@@ -263,7 +263,7 @@ in {
     (mkIf (pkgs.stdenv.isLinux && config.home.username != "root") {
       xdg.configFile = mkMerge [
         (lib.listToAttrs ((buildServices "service" cfg.services)
-          ++ (buildServices "slices" cfg.slices)
+          ++ (buildServices "slice" cfg.slices)
           ++ (buildServices "socket" cfg.sockets)
           ++ (buildServices "target" cfg.targets)
           ++ (buildServices "timer" cfg.timers)

tests/modules/systemd/default.nix

@@ -2,5 +2,6 @@
   systemd-services = ./services.nix;
   systemd-services-disabled-for-root = ./services-disabled-for-root.nix;
   systemd-session-variables = ./session-variables.nix;
+  systemd-slices = ./slices.nix;
   systemd-timers = ./timers.nix;
 }

tests/modules/systemd/slices.nix

@@ -0,0 +1,31 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+{
+  config = {
+    systemd.user.slices.app-test = {
+      Unit = { Description = "Slice for a test app"; };
+
+      Slice = {
+        MemoryHigh = "30%";
+        MemoryMax = "40%";
+      };
+    };
+
+    nmt.script = ''
+      sliceFile=home-files/.config/systemd/user/app-test.slice
+      assertFileExists $sliceFile
+      assertFileContent $sliceFile ${
+        builtins.toFile "app-test-expected.conf" ''
+          [Slice]
+          MemoryHigh=30%
+          MemoryMax=40%
+
+          [Unit]
+          Description=Slice for a test app
+        ''
+      }
+    '';
+  };
+}