nh: fix clean option behaviour for Darwin

tests/modules/programs/nh/darwin/config.nix

@@ -0,0 +1,22 @@
+{
+  programs.nh = {
+    enable = true;
+
+    flake = "/path/to/flake";
+
+    clean = {
+      enable = true;
+      dates = "weekly";
+    };
+  };
+
+  nmt.script = ''
+    serviceFile="LaunchAgents/org.nix-community.home.nh-clean.plist"
+    serviceFileNormalized="$(normalizeStorePaths "$serviceFile")"
+
+    assertFileExists $serviceFile
+    assertFileContent $serviceFileNormalized ${./launchd.plist}
+
+    assertFileRegex home-path/etc/profile.d/hm-session-vars.sh 'NH_FLAKE="/path/to/flake"'
+  '';
+}

tests/modules/programs/nh/darwin/launchd.plist

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>Label</key>
+	<string>org.nix-community.home.nh-clean</string>
+	<key>ProgramArguments</key>
+	<array>
+		<string>@nh@/bin/nh</string>
+		<string>clean</string>
+		<string>user</string>
+	</array>
+	<key>StartCalendarInterval</key>
+	<array>
+		<dict>
+			<key>Hour</key>
+			<integer>0</integer>
+			<key>Minute</key>
+			<integer>0</integer>
+			<key>Weekday</key>
+			<integer>1</integer>
+		</dict>
+	</array>
+</dict>
+</plist>

tests/modules/programs/nh/default.nix

@@ -1,4 +1,7 @@
 { lib, pkgs, ... }:
-lib.optionalAttrs pkgs.stdenv.hostPlatform.isLinux {
-  nh = ./nh.nix;
-}
+(lib.optionalAttrs pkgs.stdenv.hostPlatform.isDarwin {
+  nh = ./darwin/config.nix;
+})
+// (lib.optionalAttrs pkgs.stdenv.hostPlatform.isLinux {
+  nh = ./linux/config.nix;
+})