Add a VM test to make sure the nixos module actually works (#16)

Author: benley

flake.nix

@@ -38,6 +38,8 @@
 
         checks.tailscale-manager = self.packages.${system}.tailscale-manager;
 
+        checks.vm-test = pkgs.callPackage ./nix/vm-test.nix { inherit self; };
+
         devShells.default = pkgs.mkShell {
           buildInputs = with pkgs; [
             haskellPackages.haskell-language-server # you must build it with your ghc to work

nix/vm-test.nix

@@ -0,0 +1,23 @@
+{ self, lib, pkgs, system, ... }:
+
+let fakeTailscale = pkgs.writeScriptBin "tailscale" ''
+  #!/bin/sh
+  echo "Fake tailscale invoked with args: $*" 1>&2
+'';
+in
+pkgs.nixosTest {
+  name = "tailscale-manager";
+  nodes.machine1 = { config, pkgs, ... }: {
+    imports = [ self.nixosModules.${system}.tailscale-manager ];
+    services.tailscale.package = fakeTailscale;
+    services.tailscale-manager = {
+      enable = true;
+      routes = ["192.168.254.0/24"];
+    };
+    system.stateVersion = "24.11";
+  };
+  testScript = ''
+    machine1.wait_for_unit("tailscale-manager.service")
+    machine1.wait_for_console_text("Fake tailscale invoked with args:.*--advertise-routes=192.168.254.0/24")
+  '';
+}