diff --git a/flake.nix b/flake.nix
index c6ddf666c..7f869daa8 100644
--- a/flake.nix
+++ b/flake.nix
@@ -359,29 +359,27 @@
               mkdir $out
             '';
 
-          /*
-            nixpkgsLibTests = forAllSystems (
-              system:
-              let
-                inherit (self.packages.${system}) nix;
-                pkgs = nixpkgsFor.${system}.native;
-                testWithNix = import (nixpkgs + "/lib/tests/test-with-nix.nix") { inherit pkgs lib nix; };
-              in
-              pkgs.symlinkJoin {
-                name = "nixpkgs-lib-tests";
-                paths = [
-                  testWithNix
-                ]
-                # NOTE: nixpkgs 25.05 is being ... *creative*, and requires this dance to override
-                # the evaluator used for the test. it will break again in the future, don't worry.
-                ++ lib.optionals pkgs.stdenv.isLinux [
-                  ((pkgs.callPackage "${nixpkgs}/ci/eval" { inherit nix; }).attrpathsSuperset {
-                    evalSystem = system;
-                  })
-                ];
-              }
-            );
-          */
+          nixpkgsLibTests = forAllSystems (
+            system:
+            let
+              inherit (self.packages.${system}) nix;
+              pkgs = nixpkgsFor.${system}.native;
+              testWithNix = import (nixpkgs + "/lib/tests/test-with-nix.nix") { inherit pkgs lib nix; };
+            in
+            pkgs.symlinkJoin {
+              name = "nixpkgs-lib-tests";
+              paths = [
+                testWithNix
+              ]
+              # NOTE: nixpkgs 25.05 is being ... *creative*, and requires this dance to override
+              # the evaluator used for the test. it will break again in the future, don't worry.
+              ++ lib.optionals pkgs.stdenv.isLinux [
+                ((pkgs.callPackage "${nixpkgs}/ci/eval" { inherit nix; }).attrpathsSuperset {
+                  evalSystem = system;
+                })
+              ];
+            }
+          );
         };
 
         pre-commit = forAvailableSystems (
@@ -430,7 +428,7 @@
 
           binaryTarball = self.hydraJobs.binaryTarball.${system};
           perlBindings = self.hydraJobs.perlBindings.${system};
-          # nixpkgsLibTests = self.hydraJobs.tests.nixpkgsLibTests.${system};
+          nixpkgsLibTests = self.hydraJobs.tests.nixpkgsLibTests.${system};
           rl-next = self.hydraJobs.rl-next.${system}.user;
           # Will be empty attr set on i686-linux, and filtered out by forAvailableSystems.
           pre-commit = self.hydraJobs.pre-commit.${system};