nixos/nixpkgs.nix: Make independent

(cherry picked from commit 62e7f0eda1c5acf0beb13a00a23f577912a6b8eb)

nixos/modules/misc/nixpkgs.nix

@@ -64,6 +64,11 @@ let
 in
 
 {
+  imports = [
+    ./assertions.nix
+    ./meta.nix
+  ];
+
   options.nixpkgs = {
 
     pkgs = mkOption {

nixos/modules/misc/nixpkgs/test.nix

@@ -0,0 +1,8 @@
+{ evalMinimalConfig, pkgs, lib, stdenv }:
+lib.recurseIntoAttrs {
+  invokeNixpkgsSimple =
+    (evalMinimalConfig ({ config, modulesPath, ... }: {
+      imports = [ (modulesPath + "/misc/nixpkgs.nix") ];
+      nixpkgs.system = stdenv.hostPlatform.system;
+    }))._module.args.pkgs.hello;
+}

nixos/tests/all-tests.nix

@@ -19,6 +19,9 @@ let
   handleTestOn = systems: path: args:
     if elem system systems then handleTest path args
     else {};
+
+  nixosLib = import ../lib {};
+  evalMinimalConfig = module: nixosLib.evalModules { modules = [ module ]; };
 in
 {
   _3proxy = handleTest ./3proxy.nix {};
@@ -327,6 +330,7 @@ in
   nix-serve-ssh = handleTest ./nix-serve-ssh.nix {};
   nixops = handleTest ./nixops/default.nix {};
   nixos-generate-config = handleTest ./nixos-generate-config.nix {};
+  nixpkgs = pkgs.callPackage ../modules/misc/nixpkgs/test.nix { inherit evalMinimalConfig; };
   node-red = handleTest ./node-red.nix {};
   nomad = handleTest ./nomad.nix {};
   novacomd = handleTestOn ["x86_64-linux"] ./novacomd.nix {};