treewide: disable tests on darwin

- tthsum
- python-papis
- python-sqlalchemy-migrate
- python-xlib
- dub

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

@@ -30,6 +30,8 @@ buildPythonPackage rec {
   buildInputs = [ xorg.libX11 ];
   propagatedBuildInputs = [ six ];
 
+  doCheck = !stdenv.isDarwin;
+
   meta = with stdenv.lib; {
     description = "Fully functional X client library for Python programs";
     homepage = http://python-xlib.sourceforge.net/;