Make the module work with python3

This makes the module work with Python 3 and adds a tox target to
perform python 3.5 tests.

Makefile

@@ -4,13 +4,14 @@ PYTHON := /usr/bin/env python
 clean:
 	@rm -rf .testrepository .unit-state.db .tox .eggs charm.openstack.egg-info
 	@find . -iname '*.pyc' -delete
+	@find . -iname '__pycache__' -delete
 
 lint:
 	@tox -e pep8
 
 test:
 	@echo Starting unit tests...
-	@tox -e py27
+	@tox -e py27,py34,py35
 
 publish:
 	python setup.py publish

test-requirements.txt

@@ -1,7 +1,6 @@
 flake8>=2.2.4,<=2.4.1
 os-testr>=0.4.1
 paramiko<2.0
-charm-tools>=2.0.0
 charms.reactive
 mock>=1.2
 coverage>=3.6

tox.ini

@@ -1,6 +1,7 @@
 [tox]
-envlist = pep8,py27
+envlist = pep8,py27,py34,py35
 skipsdist = True
+skip_missing_interpreters = True
 
 [testenv]
 setenv = VIRTUAL_ENV={envdir}
@@ -13,6 +14,14 @@ commands = ostestr {posargs}
 basepython = python2.7
 deps = -r{toxinidir}/test-requirements.txt
 
+[testenv:py34]
+basepython = python3.4
+deps = -r{toxinidir}/test-requirements.txt
+
+[testenv:py35]
+basepython = python3.5
+deps = -r{toxinidir}/test-requirements.txt
+
 [testenv:pep8]
 basepython = python2.7
 deps = -r{toxinidir}/test-requirements.txt

unit_tests/test_charms_openstack_charm.py

@@ -4,12 +4,13 @@
 # mock out some charmhelpers libraries as they have apt install side effects
 # sys.modules['charmhelpers.contrib.openstack.utils'] = mock.MagicMock()
 # sys.modules['charmhelpers.contrib.network.ip'] = mock.MagicMock()
+from __future__ import absolute_import
 
 import collections
 
 import mock
 
-import utils
+import unit_tests.utils as utils
 
 import charms_openstack.charm as chm
 

unit_tests/test_charms_openstack_ip.py

@@ -5,8 +5,9 @@
 # mock out some charmhelpers libraries as they have apt install side effects
 # sys.modules['charmhelpers.contrib.openstack.utils'] = mock.MagicMock()
 # sys.modules['charmhelpers.contrib.network.ip'] = mock.MagicMock()
+from __future__ import absolute_import
 
-import utils
+import unit_tests.utils as utils
 
 import charms_openstack.ip as ip