tmpfiles: migrate to an RFC42-style option

tests/modules/misc/tmpfiles/basic-rules.nix

@@ -0,0 +1,24 @@
+{
+  imports = [ ./common-stubs.nix ];
+
+  systemd.user.tmpfiles.settings = {
+    cache."%C".d.age = "4 weeks";
+    myTool."%h/.config/myTool.conf"."f+" = {
+      mode = "0644";
+      user = "alice";
+      group = "users";
+      argument = "my unescaped config";
+    };
+  };
+
+  nmt.script = ''
+    cacheRulesFile=home-files/.config/user-tmpfiles.d/home-manager-cache.conf
+    assertFileExists $cacheRulesFile
+    assertFileRegex $cacheRulesFile "^'d' '%C' '-' '-' '-' '4 weeks' $"
+
+    myToolRulesFile=home-files/.config/user-tmpfiles.d/home-manager-myTool.conf
+    assertFileExists $myToolRulesFile
+    assertFileRegex $myToolRulesFile \
+      "^'f+' '%h/.config/myTool.conf' '0644' 'alice' 'users' '-' my\\\\x20unescaped\\\\x20config$"
+  '';
+}

tests/modules/misc/tmpfiles/common-stubs.nix

@@ -0,0 +1,3 @@
+{
+  test.stubs.systemd.outPath = null;
+}

tests/modules/misc/tmpfiles/default.nix

@@ -0,0 +1,6 @@
+{
+  tmpfiles-no-rules = ./no-rules.nix;
+  tmpfiles-basic-rules = ./basic-rules.nix;
+
+  tmpfiles-escaped-argument-warning = ./escaped-argument-warning.nix;
+}

tests/modules/misc/tmpfiles/escaped-argument-warning.nix

@@ -0,0 +1,14 @@
+{
+  imports = [ ./common-stubs.nix ];
+
+  systemd.user.tmpfiles.settings.foo.path.f.argument = "my\\x20unescaped\\x20config";
+
+  test.asserts.warnings.expected = [
+    ''
+      The 'systemd.user.tmpfiles.settings.foo.path.f.argument' option
+      appears to contain escape sequences, which will be escaped again.
+      Unescape them if this is not intended. The assigned string is:
+        "my\x20unescaped\x20config"
+    ''
+  ];
+}

tests/modules/misc/tmpfiles/no-rules.nix

@@ -0,0 +1,9 @@
+{
+  imports = [ ./common-stubs.nix ];
+
+  systemd.user.tmpfiles.settings = { };
+
+  nmt.script = ''
+    assertPathNotExists home-files/.config/user-tmpfiles.d/
+  '';
+}