Added Tox for unit testing on different versions of Python

.gitignore

@@ -1,5 +1,10 @@
 *.pyc
+.*.swp
 *.sublime-project
 *.sublime-workspace
 dist/
 MANIFEST
+/.coverage
+/.cache/
+/.tox/
+/pillar_sdk.egg-info/

.travis.yml

@@ -0,0 +1,25 @@
+language: python
+
+# Python 3.5 specified to make tox environment 'py35' work.
+# See: https://github.com/travis-ci/travis-ci/issues/4794
+python:
+  - 3.5
+
+# Environment changes have to be manually synced with 'tox.ini'.
+# See: https://github.com/travis-ci/travis-ci/issues/3024
+env:
+  - TOXENV=py27
+  - TOXENV=py34
+  - TOXENV=py35
+
+install:
+  - pip install -r requirements.txt
+  - pip install coveralls
+
+script:
+  - tox
+
+after_success:
+  # Coveralls submission only for py35 environment, because of being the only
+  # one that executes doctest-modules testing, according to tox.ini.
+  - if [ ${TOXENV} = "py35" ]; then coveralls; fi

requirements.txt

@@ -0,0 +1,10 @@
+pyOpenSSL==0.15.1
+requests==2.9.1
+six==1.10.0
+
+tox>=2.3.1
+wheel>=0.29.0
+coverage>=3.5
+PyTest
+pytest-xdist
+pytest-cov

tox.ini

@@ -0,0 +1,20 @@
+[tox]
+# Environment changes have to be manually synced with '.travis.yml'.
+envlist = py27,py34,py35
+
+[pytest]
+addopts = -v --cov pillarsdk --cov-report term-missing
+
+[testenv]
+commands=py.test []
+deps=coverage >=3.5
+     PyTest
+     pytest-xdist
+     pytest-cov
+
+; For now we skip doctests.
+;[testenv:py35]
+;commands=py.test --doctest-modules []
+
+[pep8]
+max-line-length = 100