Merge pull request #235874 from baloo/baloo/nixosTest/lib.override-support

nixosTest: adds support for lib.extend

nixos/lib/testing/nodes.nix

@@ -16,6 +16,7 @@ let
 
   baseOS =
     import ../eval-config.nix {
+      inherit lib;
       system = null; # use modularly defined system
       inherit (config.node) specialArgs;
       modules = [ config.defaults ];

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;
   };
 

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;
+}

pkgs/build-support/testers/default.nix

@@ -97,7 +97,9 @@
   # See doc/builders/testers.chapter.md or
   # https://nixos.org/manual/nixpkgs/unstable/#tester-runNixOSTest
   runNixOSTest =
-    let nixos = import ../../../nixos/lib {};
+    let nixos = import ../../../nixos/lib {
+      inherit lib;
+    };
     in testModule:
         nixos.runTest {
           _file = "pkgs.runNixOSTest implementation";