nix-serve: Make test reusable and expose linked nix in passthru (#342778)

nixos/tests/all-tests.nix

@@ -685,7 +685,7 @@ in {
   nix-misc = handleTest ./nix/misc.nix {};
   nix-upgrade = handleTest ./nix/upgrade.nix {inherit (pkgs) nixVersions;};
   nix-required-mounts = runTest ./nix-required-mounts;
-  nix-serve = handleTest ./nix-serve.nix {};
+  nix-serve = runTest ./nix-serve.nix;
   nix-serve-ssh = handleTest ./nix-serve-ssh.nix {};
   nixops = handleTest ./nixops/default.nix {};
   nixos-generate-config = handleTest ./nixos-generate-config.nix {};

nixos/tests/nix-serve.nix

@@ -1,4 +1,4 @@
-import ./make-test-python.nix ({ pkgs, ... }:
+{ config, ... }:
 {
   name = "nix-serve";
   nodes.machine = { pkgs, ... }: {
@@ -9,7 +9,7 @@ import ./make-test-python.nix ({ pkgs, ... }:
   };
   testScript = let
     pkgHash = builtins.head (
-      builtins.match "${builtins.storeDir}/([^-]+).+" (toString pkgs.hello)
+      builtins.match "${builtins.storeDir}/([^-]+).+" (toString config.node.pkgs.hello)
     );
   in ''
     start_all()
@@ -19,4 +19,4 @@ import ./make-test-python.nix ({ pkgs, ... }:
         "curl --fail -g http://0.0.0.0:5000/nar/${pkgHash}.nar -o /tmp/hello.nar"
     )
   '';
-})
+}

pkgs/tools/package-management/nix-serve/default.nix

@@ -35,6 +35,9 @@ stdenv.mkDerivation {
                 --add-flags $out/libexec/nix-serve/nix-serve.psgi
   '';
 
+  /** The nix package that nix-serve got its nix perl bindings from. */
+  passthru.nix = nix;
+
   passthru.tests = {
     nix-serve = nixosTests.nix-serve;
     nix-serve-ssh = nixosTests.nix-serve-ssh;