buildbot-worker: add link to nixos test

pkgs/development/python-modules/buildbot/worker.nix

@@ -1,5 +1,5 @@
 { lib, buildPythonPackage, fetchPypi, buildbot, setuptoolsTrial, mock, twisted,
-  future, coreutils }:
+  future, coreutils, nixosTests }:
 
 buildPythonPackage (rec {
   pname = "buildbot-worker";
@@ -19,6 +19,10 @@ buildPythonPackage (rec {
       --replace /usr/bin/tail "${coreutils}/bin/tail"
   '';
 
+  passthru.tests = {
+    smoke-test = nixosTests.buildbot;
+  };
+
   meta = with lib; {
     homepage = "https://buildbot.net/";
     description = "Buildbot Worker Daemon";