diff --git a/pkgs/development/python-modules/pydot_ng/default.nix b/pkgs/development/python-modules/pydot_ng/default.nix
index ba754e9959bf..d48ddaccd585 100644
--- a/pkgs/development/python-modules/pydot_ng/default.nix
+++ b/pkgs/development/python-modules/pydot_ng/default.nix
@@ -1,10 +1,9 @@
-{ stdenv
-, buildPythonPackage
-, fetchPypi
+{ lib, buildPythonPackage, fetchPypi, isPy27
+, graphviz
+, mock
 , pyparsing
 , pytest
 , unittest2
-, pkgs
 }:
 
 buildPythonPackage rec {
@@ -16,19 +15,22 @@ buildPythonPackage rec {
     sha256 = "8c8073b97aa7030c28118961e2c6c92f046e4cb57aeba7df87146f7baa6530c5";
   };
 
-  buildInputs = [ pytest unittest2 ];
-  propagatedBuildInputs = [ pkgs.graphviz pyparsing ];
+  propagatedBuildInputs = [ graphviz pyparsing ];
+
+  checkInputs = [
+    graphviz
+    mock
+    pytest
+  ] ++ lib.optionals isPy27 [ unittest2];
 
   checkPhase = ''
-    mkdir test/my_tests
-    py.test test
+    pytest
   '';
 
-  meta = with stdenv.lib; {
+  meta = with lib; {
     homepage = "https://pypi.python.org/pypi/pydot-ng";
     description = "Python 3-compatible update of pydot, a Python interface to Graphviz's Dot";
     license = licenses.mit;
-    maintainers = [ maintainers.bcdarwin ];
+    maintainers = with maintainers; [ bcdarwin jonringer ];
   };
-
 }
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index f319bdf7b11e..2e02ea3a7550 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -4311,7 +4311,7 @@ in {
     inherit (pkgs) graphviz;
   };
 
-  pydot_ng = callPackage ../development/python-modules/pydot_ng { };
+  pydot_ng = callPackage ../development/python-modules/pydot_ng { graphviz = pkgs.graphviz; };
 
   pyelftools = callPackage ../development/python-modules/pyelftools { };