Ensure tox gets proper language settings.

[nvtkaszpir]

If LC_ALL is not passed then the interpreter will assume it is C
(which causes the interpreter to use ASCII). This, in turn, causes
the unicode in various places to trigger a UnicodeDecodeError
exception.

CI workers have that locale set by default.
Some people do not have that locale setting set properly.

[asottile]

A couple things:

• you've got tabs ;)
• I actually think that assuming a UTF-8 locale is probably a bug, if there's things that are failing they should probably get fixed? Do you have some specific stacktraces here -- I imagine they'd make decent bug reports :)
• I think LANG is probably a better catchall than LC_ALL (iirc, LANG overrides all of the others)

[nvtkaszpir]

• argh...
• example error

_______________________________________________________________________________________________________ test_readme_contains_all_hooks ________________________________________________________________________________________________________

    def test_readme_contains_all_hooks():
>       readme_contents = io.open('README.md').read()

tests/readme_test.py:10: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <encodings.ascii.IncrementalDecoder object at 0x00000000050dcaa0>
input = "[![Build Status](https://travis-ci.org/pre-commit/pre-commit-hooks.svg?branch=master)](https://travis-ci.org/pre-comm...d like to use these hooks, they're also available as a standalone\npackage.\n\nSimply `pip install pre-commit-hooks`\n"
final = 1

    def decode(self, input, final=False):
>       return codecs.ascii_decode(input, self.errors)[0]
E       UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 1828: ordinal not in range(128)

.tox/pypy/lib-python/2.7/encodings/ascii.py:26: UnicodeDecodeError

• they work in the same way, but LC_ALL is processed in the first place, see man 7 locale. If you suggest to stick to LANG then OK.

[asottile]

Ah indeed! Looks to me like a buggy test, I believe this fixes it? #277

[nvtkaszpir]

Yep.
So my PR is no longer required. :)

[nvtkaszpir]

Hm not so fast.
Looks like it is needed also in other places, for example:
autopep8-wrapper
check-docstrings-first
reorder-python-imports

[asottile]

via #279 -- thanks again :D