nix vm tests: refactor to make gnome vm node builder reusable

nix/tests.nix

@@ -37,27 +37,11 @@
             return "${pink_value}" in text
   '';
 
-  mkTestGnome = {
-    name,
-    settings,
-    testScript,
-    ocr ? false,
-  }:
-    pkgs.testers.runNixOSTest {
-      name = name;
-
-      enableOCR = ocr;
-
-      extraBaseModules = {
-        imports = [
-          home-manager.nixosModules.home-manager
-        ];
-      };
-
-      nodes = {
-        machine = {
+  mkNodeGnome = {
     config,
     pkgs,
+    settings,
+    sshPort ? null,
     ...
   }: {
     imports = [
@@ -65,9 +49,29 @@
       settings
     ];
 
-          virtualisation.vmVariant = {
+    virtualisation = {
+      forwardPorts = pkgs.lib.optionals (sshPort != null) [
+        {
+          from = "host";
+          host.port = sshPort;
+          guest.port = 22;
+        }
+      ];
+
+      vmVariant = {
         virtualisation.host.pkgs = pkgs;
       };
+    };
+
+    services.openssh = {
+      enable = true;
+      settings = {
+        PermitRootLogin = "yes";
+        PermitEmptyPasswords = "yes";
+      };
+    };
+
+    security.pam.services.sshd.allowNullPassword = true;
 
     users.groups.ghostty = {
       gid = 1000;
@@ -91,6 +95,34 @@
 
     system.stateVersion = nixos-version;
   };
+
+  mkTestGnome = {
+    name,
+    settings,
+    testScript,
+    ocr ? false,
+  }:
+    pkgs.testers.runNixOSTest {
+      name = name;
+
+      enableOCR = ocr;
+
+      extraBaseModules = {
+        imports = [
+          home-manager.nixosModules.home-manager
+        ];
+      };
+
+      nodes = {
+        machine = {
+          config,
+          pkgs,
+          ...
+        }:
+          mkNodeGnome {
+            inherit config pkgs settings;
+            sshPort = 2222;
+          };
       };
 
       testScript = testScript;