[Python-Dev] Mountain Lion drops sign of zero, breaks test_cmath...

[R. David Murray]

On Fri, 17 Aug 2012 04:00:50 -0400, Trent Nelson <trent at snakebite.org> wrote:
>     This is the patch I came up with against test_cmath.py:
> 
> xenon% hg diff Lib/test/test_cmath.py
> diff -r ce49599b9fdf Lib/test/test_cmath.py
> --- a/Lib/test/test_cmath.py    Thu Aug 16 22:14:43 2012 +0200
> +++ b/Lib/test/test_cmath.py    Fri Aug 17 07:54:05 2012 +0000
> @@ -121,8 +121,10 @@
>          # if both a and b are zero, check whether they have the same sign
>          # (in theory there are examples where it would be legitimate for a
>          # and b to have opposite signs; in practice these hardly ever
> -        # occur).
> -        if not a and not b:
> +        # occur) -- the exception to this is if we're on a system that drops
> +        # the sign on zeros.
> +        drops_zero_sign = sysconfig.get_config_var('LOG1P_DROPS_ZERO_SIGN')
> +        if not drops_zero_sign and not a and not b:
>              if math.copysign(1., a) != math.copysign(1., b):
>                  self.fail(msg or 'zero has wrong sign: expected {!r}, '
>                            'got {!r}'.format(a, b))
> 
>     With that applied, all the test_cmath tests pass again (without any
>     changes to the test file).
> 
>     Thoughts?

Open an issue on the tracker and make mark.dickinson (and maybe skrah)
nosy.

--David