[issue14521] math.copysign(1., float('nan')) returns -1.

[mattip]

mattip <matti.picus at gmail.com> added the comment:

Your patch is much more reasonable than mine.
Should I add a test that fails pre-patch and passes with the patch, or one that is skipped pre-patch and passes post-patch? I'm not sure what is accepted in the cpython development cycle

----------

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue14521>
_______________________________________