Python3 locale inconsistencies

encodings.py

#!/bin/env python
# vim: ts=4 sts=4 sw=4 ft=python expandtab fileencoding=utf8 :

""" Python2 and Python3 differ on how they handle input and output 
files depending on the current locale.

Python2: behaves consistently(but badly), reading and writing utf8 
  as if it was ascii. Successfully giving back the same byte sequence
  as was put in. (Aka. The same string)

Python3: Tests if "utf8" is in your LANG environment, and that 
  `setlocale` for the selected setting works, 
  otherwise falls back to "ascii"

Python3 will also behave differently on Windows and OS X.
OS X hard coded to utf8, windows doing... Something else, entirely.
That only makes this harder to detect until it bites you in the face."""

try:
    import ConfigParser as configparser
except ImportError:
    import configparser
import locale

BASE="räksmörgås"
FNAME="testfile.ini"

config = configparser.SafeConfigParser()
config.add_section(BASE)
config.set(BASE, "testing", "With some unicode")

with open(FNAME, "w") as f:
    config.write(f)

config = configparser.SafeConfigParser()
with open(FNAME, "r") as f:
    config.readfp(f)

To show the different behaviours, run it with

LANG=en_GB.UTF-8 LC_ALL=en_GB.UTF-8 python2 test.py
LANG=C LC_ALL=C python2 test.py

LANG=en_GB.UTF-8 LC_ALL=en_GB.UTF-8 python3 test.py
LANG=C LC_ALL=C python3 test.py