diff --git a/tests/main.nix b/tests/main.nix
index ec98b2ba..648c341d 100644
--- a/tests/main.nix
+++ b/tests/main.nix
@@ -37,6 +37,9 @@ let
             imports = lib.toList module;
           }
         ];
+        extraSpecialArgs = {
+          helpers = throw "nixvim: `helpers` used internally.";
+        };
       };
     in
     configuration.config.build.test.overrideAttrs (old: {