[Distutils] Accessing tests_require and setup_requires from the setup.py

[Christopher Baines]

I'm trying to write a script to get information about a source
distributions requirements (from the source distribution), but I'm not
sure how to access the tests_require and setup_requires that can
sometimes be found in the setup.py?

Apologies if this is really simple, and I've just missed the answer, but
I've searched for it a few times now, and not come up with anything.

Thanks,

Chris