Fix tests for python3 using decode() on pipe output

[eliasdorneles]

Hey folks,

So, this needs more testing, it just adds some tricks to fix the current tests for Python 3, I'm not sure how much this means for Python 3 compatibility yet.

This basically just adds .decode() to the places where are expected bytes in Python 3 (pipe outputs) -- plus some minor refactorings.

The encoding should be ascii for all outputs, not sure if I should be explicit about it.

@kmike any advice here? :)

[kmike]

.decode() and .encode() use sys.getdefaultencoding() encoding, which is usually ASCII. For pipes it may be better to use sys.stdout.encoding / sys.stdin.encoding with some fallback for the cases these encodings are not set (utf8?).

[pablohoffman]

who should merge this?

[eliasdorneles]

@pablohoffman Ahm, allow me to apply Mike's advice first, and then you or @josericardo can review & merge.

You'd have to run the tests locally with tox, which will run them for python 3.
Travis is only running them for Python 2, perhaps I should enable python 3 tests as part of this PR?

[eliasdorneles]

updated and rebased!