added test-build

modules/nix-tools/rebuild.nix

@@ -1,8 +1,9 @@
-{ inputs, ... }:
+{ self, inputs, ... }:
 {
   flake.modules.homeManager.rebuild =
     { pkgs, lib, config, ... }:
     let
+      nixBin = lib.getExe pkgs.nix;
       flakeDir = config.homeManagerFlakeDir;
       echoCmd = lib.getExe' pkgs.coreutils "echo";
       hostnameCmd = "$(${lib.getExe pkgs.hostname} -s)";
@@ -31,10 +32,7 @@
         };
       };
 
-      config = let
+      config = {
-        nixBin = lib.getExe pkgs.nix;
-      in
-      {
         home.activation.printFlakeDir = lib.hm.dag.entryAfter ["writeBoundary"] ''
           run ${echoCmd} "Home Manager flake directory: ${flakeDir}"
         '';
@@ -69,6 +67,15 @@
             ${lib.getExe git} -C ${flakeDir} add ${flakeDir}/flake.lock > /dev/null 2>&1
             ${lib.getExe nfs}
           '')
+          (writeShellScriptBin "test-build" ''
+            if [ -z "$1" ]; then
+              HOSTNAME=${hostnameCmd}
+            else
+              HOSTNAME="$1"
+            fi
+            ${echoCmd} "Testing the evaulation of the nixos config for $HOSTNAME"
+            ${nixBin} eval ${flakeDir}#nixosConfigurations.$HOSTNAME.config.system.build.toplevel.drvPath
+          '')
         ];
       };
     };