Antoine Pitrou added the comment:

Are there tests for this?

Not sure what you mean: there are several tests using isatty() in test suite. Regardless, there is no #ifdef around the isatty() definition in posixmodule.c, so I can only assume it exists on all platforms. ---------- nosy: +pitrou _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue18553> _______________________________________