anchor.diff:  
     propagatedBuildInputs = [ fonttools lxml fs ];
   
  -  checkInputs = [ pytest pytestcov pytest_xdist pytest-randomly ];
  -  checkPhase = "pytest tests";
  +  checkInputs = [
  +    # Override pytestCheckHook to use pytest v5, because some tests fail on pytest >= v6
  +    # https://github.com/adobe-type-tools/psautohint/issues/284#issuecomment-742800965
  +    # Override might be able to be removed in future, check package dependency pins (coverage.yml)
  +    (pytestCheckHook.override{ pytest = pytest_5; })
  +    pytestcov
  +    pytest_xdist
  +  ];
  +  disabledTests = [
  +    # Slow tests, reduces test time from ~5 mins to ~30s
  +    "test_mmufo"
  +    "test_flex_ufo"
  +    "test_ufo"
  +    "test_flex_otf"
  +    "test_multi_outpath"
  +    "test_mmhint"
  +    "test_otf"
  +  ];
   
     meta = with lib; {
       description = "Script to normalize the XML and other data inside of a UFO";
  
positive.code:   disabled = pythonOlder "3.6";
  
    src = fetchFromGitHub {
      owner  = "adobe-type-tools";
      repo   = pname;
      sha256 = "1s2l54gzn11y07zaggprwif7r3ia244qijjhkbvjdx4jsgc5df8n";
      rev    = "v${version}";
      fetchSubmodules = true; # data dir for tests
    };
  
  
negative.code: { lib, buildPythonPackage, fetchFromGitHub, pythonOlder
  , fonttools, lxml, fs
  , setuptools_scm
  , pytestCheckHook, pytest_5, pytestcov, pytest_xdist
  }:
  
  buildPythonPackage rec {
  