diff --git a/pkgs/development/python-modules/demjson/default.nix b/pkgs/development/python-modules/demjson/default.nix
index 9cd39c34ea0..aee130f789e 100644
--- a/pkgs/development/python-modules/demjson/default.nix
+++ b/pkgs/development/python-modules/demjson/default.nix
@@ -1,17 +1,19 @@
-{ stdenv, buildPythonPackage, fetchPypi, isPy3k }:
+{ stdenv, python, buildPythonPackage, fetchPypi, isPy3k }:
 
 buildPythonPackage rec {
   pname = "demjson";
   version = "2.2.4";
-  disabled = isPy3k;
 
   src = fetchPypi {
     inherit pname version;
     sha256 = "0ygbddpnvp5lby6mr5kz60la3hkvwwzv3wwb3z0w9ngxl0w21pii";
   };
 
-  doCheck = false;
-  pythonImportsCheck = [ "demjson" ];
+  checkPhase = stdenv.lib.optionalString isPy3k ''
+    ${python.interpreter} -m lib2to3 -w test/test_demjson.py
+  '' + ''
+    ${python.interpreter} test/test_demjson.py
+  '';
 
   meta = with stdenv.lib; {
     description = "Encoder/decoder and lint/validator for JSON (JavaScript Object Notation)";