nixosTests.activation-lib: don't use fileset

nixos/modules/system/activation/lib-test.nix

@@ -10,13 +10,7 @@ let
 
   runTests = stdenv.mkDerivation {
     name = "tests-activation-lib";
-    src = fileset.toSource {
-      root = ./.;
-      fileset = fileset.unions [
-        ./lib.sh
-        ./test.sh
-      ];
-    };
+    src = ./lib;
     buildPhase = ":";
     doCheck = true;
     postUnpack = ''

nixos/tests/all-tests.nix

@@ -200,7 +200,7 @@ in
   activation-bashless-image = runTest ./activation/bashless-image.nix;
   activation-etc-overlay-immutable = runTest ./activation/etc-overlay-immutable.nix;
   activation-etc-overlay-mutable = runTest ./activation/etc-overlay-mutable.nix;
-  activation-lib = pkgs.callPackage ../modules/system/activation/lib/test.nix { };
+  activation-lib = pkgs.callPackage ../modules/system/activation/lib-test.nix { };
   activation-nix-channel = runTest ./activation/nix-channel.nix;
   activation-nixos-init = runTest ./activation/nixos-init.nix;
   activation-perlless = runTest ./activation/perlless.nix;