pythonPackages.mock: have 3.0.5 for python 2, disable tests python 3

because of circular dependency.

pkgs/development/python-modules/mock/default.nix

@@ -6,6 +6,7 @@
 , six
 , pbr
 , python
+, pytest
 }:
 
 buildPythonPackage rec {
@@ -23,12 +24,17 @@ buildPythonPackage rec {
   # Mock upstream has a decoration to disable the failing test and make
   # everything pass, but it is not yet released. The commit:
   # https://github.com/testing-cabal/mock/commit/73bfd51b7185#diff-354f30a63fb0907d4ad57269548329e3L12
-  doCheck = !(python.isPyPy && python.isPy27);
+  #doCheck = !(python.isPyPy && python.isPy27);
+  doCheck = false; # Infinite recursion pytest
 
   checkPhase = ''
     ${python.interpreter} -m unittest discover
   '';
 
+  checkInputs = [
+    pytest
+  ];
+
   meta = with lib; {
     description = "Mock objects for Python";
     homepage = "http://python-mock.sourceforge.net/";