nix: a services.nxdns module that runs the packaged unit in file mode against a configuration the pinned binary accepted

flake.nix

@@ -4,7 +4,7 @@
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
 
   outputs =
-    { nixpkgs, ... }:
+    { self, nixpkgs, ... }:
     let
       # `zig build cut` rewrites the lines between the delimiters by text replacement.
       # BEGIN GENERATED BY zig build cut
@@ -46,6 +46,9 @@
             runHook preInstall
 
             install -Dm755 nxdns $out/bin/nxdns
+            install -Dm644 nxdns.service $out/lib/systemd/system/nxdns.service
+            substituteInPlace $out/lib/systemd/system/nxdns.service \
+              --replace-fail "ExecStart=/usr/local/bin/nxdns run" "ExecStart=$out/bin/nxdns run"
             install -Dm644 LICENSE $out/share/doc/nxdns/LICENSE
             install -Dm644 THIRD-PARTY-NOTICES $out/share/doc/nxdns/THIRD-PARTY-NOTICES
 
@@ -110,5 +113,12 @@
       packages = nixpkgs.lib.genAttrs systems (system: {
         default = package system;
       });
+
+      nixosModules.default = import ./nix/module.nix { inherit self; };
+
+      checks.x86_64-linux = import ./nix/tests.nix {
+        inherit self;
+        pkgs = nixpkgs.legacyPackages.x86_64-linux;
+      };
     };
 }