anchor.diff:  { lib, buildPythonPackage, pythonOlder, fetchPypi, isPy3k, isPyPy
   , atomicwrites
   , attrs
  -, funcsigs
   , hypothesis
   , iniconfig
  -, mock
   , more-itertools
   , packaging
   , pathlib2
   , pluggy
   , py
   , pygments
  -, python
   , setuptools
  -, setuptools_scm
  +, setuptools-scm
   , six
   , toml
   , wcwidth
  
positive.code:     toml
      wcwidth
    ] ++ lib.optionals (pythonOlder "3.6") [ pathlib2 ];
  
    doCheck = !isPyPy; # https://github.com/pytest-dev/pytest/issues/3460
  
  
negative.code:   ];
  
    meta = with lib; {
      description = "Framework for writing tests";
      homepage = "https://docs.pytest.org";
      changelog = "https://github.com/pytest-dev/pytest/releases/tag/${version}";
      maintainers = with maintainers; [ domenkozar lovek323 madjar lsix ];
      license = licenses.mit;
    };
  