diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index 1b90b3e13807..02bef2039075 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -87,6 +87,7 @@ in {
   # Testing the test driver
   nixos-test-driver = {
     extra-python-packages = handleTest ./nixos-test-driver/extra-python-packages.nix {};
+    lib-extend = handleTestOn [ "x86_64-linux" "aarch64-linux" ] ./nixos-test-driver/lib-extend.nix {};
     node-name = runTest ./nixos-test-driver/node-name.nix;
   };
 
diff --git a/nixos/tests/nixos-test-driver/lib-extend.nix b/nixos/tests/nixos-test-driver/lib-extend.nix
new file mode 100644
index 000000000000..4fb7cf494aed
--- /dev/null
+++ b/nixos/tests/nixos-test-driver/lib-extend.nix
@@ -0,0 +1,31 @@
+{ pkgs, ... }:
+
+let
+  patchedPkgs = pkgs.extend (new: old: {
+    lib = old.lib.extend (self: super: {
+      sorry_dave = "sorry dave";
+    });
+  });
+
+  testBody = {
+    name = "demo lib overlay";
+
+    nodes = {
+      machine = { lib, ... }: {
+        environment.etc."got-lib-overlay".text = lib.sorry_dave;
+      };
+    };
+
+    # We don't need to run an actual test. Instead we build the `machine` configuration
+    # and call it a day, because that already proves that `lib` is wired up correctly.
+    # See the attrset returned at the bottom of this file.
+    testScript = "";
+  };
+
+  inherit (patchedPkgs.testers) nixosTest runNixOSTest;
+  evaluationNixosTest = nixosTest testBody;
+  evaluationRunNixOSTest = runNixOSTest testBody;
+in {
+  nixosTest = evaluationNixosTest.driver.nodes.machine.system.build.toplevel;
+  runNixOSTest = evaluationRunNixOSTest.driver.nodes.machine.system.build.toplevel;
+}