diff --git a/tests/tests/think-gtcm.nix b/tests/tests/think-gtcm.nix
index 1e1bd19..44a8d61 100644
--- a/tests/tests/think-gtcm.nix
+++ b/tests/tests/think-gtcm.nix
@@ -5,6 +5,7 @@
     node1 =
       { self, pkgs, ... }:
       {
+        nixpkgs.overlays = [ self.overlays.packagesOverlay ];
         imports = [ self.nixosModules.think-gtcm ];
         services.think-greaterchiangmai = {
           enable = true;