diff --git a/dev/tests/template.nix b/dev/tests/template.nix
index 04671fa..fc4ff39 100644
--- a/dev/tests/template.nix
+++ b/dev/tests/template.nix
@@ -15,18 +15,17 @@ hci-effects.mkEffect {
     nix -v flake init -t ${../..}
 
     ann pointing to local sources...
-    sed -i flake.nix -e 's^nixpkgs.url = ".*";^nixpkgs.url = "${path}"; flake-parts.url = "${../..}";^'
-    # head flake.nix
-    grep -F ${path} flake.nix >/dev/null
+
+    override=(--override-input flake-parts ${../..})
 
     ann nix flake lock...
-    nix flake lock
+    nix flake lock "''${override[@]}"
 
     ann nix flake show...
-    nix -v flake show
+    nix -v flake show "''${override[@]}"
 
     ann nix build...
-    nix build .
+    nix build . "''${override[@]}"
 
     ann checking result...
     readlink ./result | grep hello
diff --git a/template/default/flake.nix b/template/default/flake.nix
index 929e34f..277e25f 100644
--- a/template/default/flake.nix
+++ b/template/default/flake.nix
@@ -2,6 +2,7 @@
   description = "Description for the project";
 
   inputs = {
+    flake-parts.url = "github:hercules-ci/flake-parts";
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
   };
 
diff --git a/template/multi-module/flake.nix b/template/multi-module/flake.nix
index 82cd3bd..2c5d668 100644
--- a/template/multi-module/flake.nix
+++ b/template/multi-module/flake.nix
@@ -2,6 +2,7 @@
   description = "Description for the project";
 
   inputs = {
+    flake-parts.url = "github:hercules-ci/flake-parts";
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
   };
 
diff --git a/template/package/flake.nix b/template/package/flake.nix
index 385e6cb..6cd781e 100644
--- a/template/package/flake.nix
+++ b/template/package/flake.nix
@@ -2,6 +2,7 @@
   description = "Description for the project";
 
   inputs = {
+    flake-parts.url = "github:hercules-ci/flake-parts";
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
   };
 
diff --git a/template/unfree/flake.nix b/template/unfree/flake.nix
index 7ec00c3..33eaaf2 100644
--- a/template/unfree/flake.nix
+++ b/template/unfree/flake.nix
@@ -1,7 +1,10 @@
 {
   description = "Description for the project";
 
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  inputs = {
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
 
   outputs = inputs@{ flake-parts, nixpkgs, ... }:
     flake-parts.lib.mkFlake { inherit inputs; } {