flake.nix: add *-vm packages to boot hosts in a test virtual machine

Requested-By: poelzi

flake.nix

@@ -181,11 +181,18 @@
             '';
           }) {} (builtins.attrNames flakifiedHosts) //
 
-        builtins.foldl' (result: host: result // {
-          "${host}-sdImage" = self.nixosConfigurations."${host}".config.system.build.sdImage;
-        }) {} (builtins.attrNames (nixpkgs.lib.filterAttrs (host: nixosConfiguration:
-          nixosConfiguration.config.system.build ? sdImage
-        ) self.nixosConfigurations))
+        builtins.foldl' (result: host:
+          let
+            inherit (self.nixosConfigurations.${host}) config;
+          in
+            result //
+            nixpkgs.lib.optionalAttrs (config.system.build ? sdImage) {
+              "${host}-sdImage" = config.system.build.sdImage;
+            } //
+            nixpkgs.lib.optionalAttrs (config.system.build ? vm) {
+              "${host}-vm" = config.system.build.vm;
+            }
+        ) {} (builtins.attrNames self.nixosConfigurations)
       ) self.legacyPackages;
 
       nixosConfigurations = let