add data model test for TF

deployment/check/data-model-ssh/nixosTest.nix

@@ -58,10 +58,10 @@ in
     };
 
   extraTestScript = ''
-    with subtest("ssh: Check the status before deployment"):
+    with subtest("Check the status before deployment"):
       ssh.fail("hello 1>&2")
 
-    with subtest("ssh: Run the deployment"):
+    with subtest("Run the deployment"):
       deployer.succeed("""
         set -euo pipefail
 

deployment/nixos.nix

@@ -11,13 +11,15 @@ let
     };
     modules = [ configuration ];
   };
-  os = {
-    inherit (eval) pkgs config options;
-    system = eval.config.system.build.toplevel;
-    inherit (eval.config.system.build) vm vmWithBootLoader;
-  };
+  toplevel =
+    {
+      inherit (eval) pkgs config options;
+      system = eval.config.system.build.toplevel;
+      inherit (eval.config.system.build) vm vmWithBootLoader;
+    }
+    .config.system.build.toplevel;
 in
 {
-  drv_path = os.config.system.build.toplevel.drvPath;
-  out_path = os.config.system.build.toplevel;
+  drv_path = toplevel.drvPath;
+  out_path = toplevel;
 }