diff --git a/pymaven/__init__.py b/pymaven/__init__.py
index 4e64be6..bd33c57 100644
--- a/pymaven/__init__.py
+++ b/pymaven/__init__.py
@@ -19,5 +19,4 @@
 from .versioning import Version
 from .versioning import VersionRange
 
-
 __all__ = ["Artifact", "Version", "VersionRange"]
diff --git a/pymaven/artifact.py b/pymaven/artifact.py
index 914f617..4c10834 100644
--- a/pymaven/artifact.py
+++ b/pymaven/artifact.py
@@ -20,11 +20,17 @@
 in a maven repository
 """
 
+import functools
 import re
+import sys
+
+import six
 
 from .errors import ArtifactParseError
 from .versioning import VersionRange
 
+if sys.version_info > (2,):
+    from .utils import cmp
 
 MAVEN_COORDINATE_RE = re.compile(
     r'(?P<group_id>[^:]+)'
@@ -34,6 +40,7 @@
     )
 
 
+@functools.total_ordering
 class Artifact(object):
     """Represents an artifact within a maven repository."""
 
@@ -69,22 +76,18 @@ def __init__(self, coordinate):
     def __cmp__(self, other):
         if self is other:
             return 0
-
         if not isinstance(other, Artifact):
-            if isinstance(other, basestring):
+            if isinstance(other, six.string_types):
                 try:
                     return cmp(self, Artifact(other))
                 except ArtifactParseError:
                     pass
             return 1
-
         result = cmp(self.group_id, other.group_id)
         if result == 0:
             result = cmp(self.artifact_id, other.artifact_id)
-
             if result == 0:
                 result = cmp(self.type, other.type)
-
                 if result == 0:
                     if self.classifier is None:
                         if other.classifier is not None:
@@ -94,13 +97,20 @@ def __cmp__(self, other):
                             result = -1
                         else:
                             result = cmp(self.classifier, other.classifier)
-
                     if result == 0:
                         result = cmp(self.version.version,
                                      other.version.version)
-
         return result
 
+    def __eq__(self, other):
+        return self.__cmp__(other) == 0
+
+    def __lt__(self, other):
+        return self.__cmp__(other) < 0
+
+    def __ne__(self, other):
+        return self.__cmp__(other) != 0
+
     def __hash__(self):
         return hash((self.group_id, self.artifact_id, self.version, self.type,
                      self.classifier))
diff --git a/pymaven/client.py b/pymaven/client.py
index ab45454..49e2b26 100644
--- a/pymaven/client.py
+++ b/pymaven/client.py
@@ -15,12 +15,6 @@
 #
 
 
-try:
-    from xml.etree import cElementTree as ElementTree
-except ImportError:
-    from xml.etree import ElementTree
-
-from urlparse import urlparse
 import getpass
 import hashlib
 import json
@@ -28,7 +22,9 @@
 import os
 import posixpath
 
+from six.moves.urllib.parse import urlparse
 import requests
+import six
 
 from . import utils
 from .artifact import Artifact
@@ -37,6 +33,10 @@
 from .pom import Pom
 from .versioning import VersionRange
 
+try:
+    from xml.etree import cElementTree as ElementTree
+except ImportError:
+    from xml.etree import ElementTree
 
 log = logging.getLogger(__name__)
 
@@ -75,7 +75,7 @@ def __init__(self, cacheDir=None):
         if cacheDir is None:
             cacheDir = "/tmp/%s-maven-cache" % getpass.getuser()
         if not os.path.exists(cacheDir):
-            os.makedirs(cacheDir, mode=0700)
+            os.makedirs(cacheDir, mode=0o700)
         self.cacheDir = cacheDir
 
     def _gen_key(self, method, uri, query_params):
@@ -155,7 +155,7 @@ class MavenClient(object):
     """ Client for talking to a maven repository
     """
     def __init__(self, *urls):
-        if isinstance(urls, basestring):
+        if isinstance(urls, six.string_types):
             urls = [urls]
         self._repos = []
         for url in urls:
diff --git a/pymaven/pom.py b/pymaven/pom.py
index b66a5fd..ee81da5 100644
--- a/pymaven/pom.py
+++ b/pymaven/pom.py
@@ -20,12 +20,12 @@
 import re
 
 from lxml import etree
+import six
 
 from .artifact import Artifact
 from .utils import memoize
 from .versioning import VersionRange
 
-
 POM_PARSER = etree.XMLParser(
     recover=True,
     remove_comments=True,
@@ -286,15 +286,15 @@ def dependencies(self):
                 ((group, artifact, str(version)), True))
 
         for key, value in itertools.chain(
-                self._find_import_deps().iteritems(),
-                self._find_deps().iteritems(),
-                self._find_relocations().iteritems()):
+                six.iteritems(self._find_import_deps()),
+                six.iteritems(self._find_deps()),
+                six.iteritems(self._find_relocations())):
             dependencies.setdefault(key, set()).update(value)
 
         for profile in self._find_profiles():
             for key, value in itertools.chain(
-                    self._find_deps(profile).iteritems(),
-                    self._find_relocations(profile).iteritems()):
+                    six.iteritems(self._find_deps(profile)),
+                    six.iteritems(self._find_relocations(profile))):
                 dependencies.setdefault(key, set()).update(value)
 
         return dependencies
diff --git a/pymaven/utils.py b/pymaven/utils.py
index 8086029..9c94075 100644
--- a/pymaven/utils.py
+++ b/pymaven/utils.py
@@ -16,9 +16,28 @@
 
 
 from functools import wraps
-from urlparse import urlsplit, urlunsplit
 import posixpath
 
+from six.moves.urllib.parse import urlsplit
+from six.moves.urllib.parse import urlunsplit
+
+
+def cmp(x, y):
+    """
+    Replacement for built-in funciton cmp that was removed in Python 3
+
+    Compare the two objects x and y and return an integer according to
+    the outcome. The return value is negative if x < y, zero if x == y
+    and strictly positive if x > y.
+    """
+    if x is None and y is None:
+        return 0
+    elif x is None:
+        return -1
+    elif y is None:
+        return 1
+    return (x > y) - (x < y)
+
 
 def memoize(name):
     def wrap(func):
diff --git a/pymaven/versioning.py b/pymaven/versioning.py
index 63570ca..e89de6c 100644
--- a/pymaven/versioning.py
+++ b/pymaven/versioning.py
@@ -19,11 +19,17 @@
 Versioning of artifacts
 """
 
-import itertools
+import functools
+import sys
+
+from six.moves import zip_longest
+import six
 
 from .errors import RestrictionParseError
 from .errors import VersionRangeParseError
 
+if sys.version_info > (2,):
+    from .utils import cmp
 
 EXCLUSIVE_CLOSE = ')'
 EXCLUSIVE_OPEN = '('
@@ -45,6 +51,7 @@ def list2tuple(l):
     return tuple(list2tuple(x) if isinstance(x, list) else x for x in l)
 
 
+@functools.total_ordering
 class Restriction(object):
     """Describes a restriction in versioning
     """
@@ -127,9 +134,9 @@ def __cmp__(self, other):
         if self is other:
             return 0
 
-        if not isinstance(other, Restriction):
-            if isinstance(other, basestring):
-                return cmp(self, Restriction(other))
+        if not isinstance(other, self.__class__):
+            if isinstance(other, six.string_types):
+                return cmp(self, self.__class__(other))
             return 1
 
         result = cmp(self.lower_bound, other.lower_bound)
@@ -143,10 +150,19 @@ def __cmp__(self, other):
                                  other.upper_bound_inclusive)
         return result
 
+    def __eq__(self, other):
+        return self.__cmp__(other) == 0
+
     def __hash__(self):
         return hash((self.lower_bound, self.lower_bound_inclusive,
                      self.upper_bound, self.upper_bound_inclusive))
 
+    def __lt__(self, other):
+        return self.__cmp__(other) < 0
+
+    def __ne__(self, other):
+        return self.__cmp__(other) != 0
+
     def __str__(self):
         s = "{open}{lower}{comma}{upper}{close}".format(
             open=(INCLUSIVE_OPEN if self.lower_bound_inclusive
@@ -170,11 +186,12 @@ def __repr__(self):
             self.upper_bound_inclusive,
             )
 
-    @staticmethod
-    def fromstring(self, spec):
-        return Restriction(spec)
+    @classmethod
+    def fromstring(cls, spec):
+        return cls(spec)
 
 
+@functools.total_ordering
 class VersionRange(object):
     """Version range specification
 
@@ -242,9 +259,9 @@ def __cmp__(self, other):
         if self is other:
             return 0
 
-        if not isinstance(other, VersionRange):
-            if isinstance(other, basestring):
-                return cmp(self, VersionRange(other))
+        if not isinstance(other, self.__class__):
+            if isinstance(other, six.string_types):
+                return cmp(self, self.__class__(other))
             elif isinstance(other, Version):
                 return cmp(other, self)
             return 1
@@ -258,9 +275,18 @@ def __cmp__(self, other):
     def __contains__(self, version):
         return any((version in r) for r in self.restrictions)
 
+    def __eq__(self, other):
+        return self.__cmp__(other) == 0
+
     def __hash__(self):
         return hash((self.version, self.restrictions))
 
+    def __lt__(self, other):
+        return self.__cmp__(other) < 0
+
+    def __ne__(self, other):
+        return self.__cmp__(other) != 0
+
     def __str__(self):
         if self.version:
             return str(self.version)
@@ -283,13 +309,13 @@ def _intersection(self, l1, l2):
         """
         raise NotImplementedError
 
-    @staticmethod
-    def fromstring(spec):
-        return VersionRange(spec)
+    @classmethod
+    def fromstring(cls, spec):
+        return cls(spec)
 
-    @staticmethod
-    def from_version(version):
-        return VersionRange(str(version))
+    @classmethod
+    def from_version(cls, version):
+        return cls(str(version))
 
     def restrict(self, version_range):
         """Returns a new VersionRange that is a restriction of this
@@ -313,6 +339,7 @@ def match_version(self, versions):
         return matched
 
 
+@functools.total_ordering
 class Version(object):
     """Maven version objecjt
     """
@@ -386,18 +413,27 @@ def __cmp__(self, other):
         if self is other:
             return 0
 
-        if not isinstance(other, Version):
-            if isinstance(other, basestring):
-                return self._compare(self._parsed, Version(other)._parsed)
+        if not isinstance(other, self.__class__):
+            if isinstance(other, six.string_types):
+                return self._compare(self._parsed, self.__class__(other)._parsed)
             elif isinstance(other, VersionRange) and other.version:
                 return self._compare(self._parsed, other.version._parsed)
             return 1
 
         return self._compare(self._parsed, other._parsed)
 
+    def __eq__(self, other):
+        return self.__cmp__(other) == 0
+
     def __hash__(self):
         return hash(self._unparsed)
 
+    def __lt__(self, other):
+        return self.__cmp__(other) < 0
+
+    def __ne__(self, other):
+        return self.__cmp__(other) != 0
+
     def __repr__(self):
         return "<%s.%s(%r)>" % (self.__module__, "Version", self._unparsed)
 
@@ -407,7 +443,7 @@ def __str__(self):
     def _compare(self, this, other):
         if isinstance(this, int):
             return self._int_compare(this, other)
-        elif isinstance(this, basestring):
+        elif isinstance(this, six.string_types):
             return self._string_compare(this, other)
         elif isinstance(this, (list, tuple)):
             return self._list_compare(this, other)
@@ -417,7 +453,7 @@ def _compare(self, this, other):
     def _int_compare(self, this, other):
         if isinstance(other, int):
             return this - other
-        elif isinstance(other, (basestring, list, tuple)):
+        elif isinstance(other, (six.string_types, list, tuple)):
             return 1
         elif other is None:
             return this
@@ -431,10 +467,10 @@ def _list_compare(self, l, other):
             return self._compare(l[0], other)
         if isinstance(other, int):
             return -1
-        elif isinstance(other, basestring):
+        elif isinstance(other, six.string_types):
             return 1
         elif isinstance(other, (list, tuple)):
-            for left, right in itertools.izip_longest(l, other):
+            for left, right in zip_longest(l, other):
                 if left is None:
                     if right is None:
                         result = 0
@@ -482,7 +518,7 @@ def _string_compare(self, s, other):
 
         if isinstance(other, (int, list, tuple)):
             return -1
-        elif isinstance(other, basestring):
+        elif isinstance(other, six.string_types):
             s_value = self._string_value(s)
             other_value = self._string_value(other)
             if s_value < other_value:
@@ -530,6 +566,6 @@ def _string_value(self, s):
 
         return "%d-%s" % (len(QUALIFIERS), s)
 
-    @staticmethod
-    def fromstring(spec):
-        return Version(spec)
+    @classmethod
+    def fromstring(cls, spec):
+        return cls(spec)
diff --git a/requirements.txt b/requirements.txt
index 8cbed91..49d9dc2 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,3 @@
 lxml>=3.4.4,<4.0.0
 requests>=2.7.0,<3.0.0
+six>=1.10,<2.0
diff --git a/setup.cfg b/setup.cfg
index 186c94c..3cea5ef 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -38,23 +38,18 @@ precision = 2
 
 [tool:pytest]
 norecursedirs =
+    .eggs
+    .env
     .git
     .tox
-    .env
-    dist
     build
-    south_migrations
+    dist
     migrations
+    south_migrations
 python_files =
     test_*.py
     *_test.py
     tests.py
-addopts =
-    -rxEfsw
-    --strict
-    --doctest-modules
-    --doctest-glob=\*.rst
-    --tb=short
 
 [isort]
 force_single_line = true
diff --git a/setup.py b/setup.py
index affee71..bd31750 100644
--- a/setup.py
+++ b/setup.py
@@ -20,7 +20,6 @@
 
 from setuptools import setup
 
-
 setup(
     setup_requires=["pbr>=1.9", "setuptools>=17.1"],
     pbr=True,
diff --git a/tests/test_client.py b/tests/test_client.py
index 2c7b1c4..3fc5c9c 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -15,12 +15,11 @@
 #
 
 
-from StringIO import StringIO
 import os
 import tempfile
 import unittest
 
-import mock
+from six import StringIO
 import requests
 
 from pymaven import Artifact
@@ -28,8 +27,13 @@
 from pymaven.client import LocalRepository
 from pymaven.client import MavenClient
 from pymaven.client import Struct
-from pymaven.errors import MissingPathError
 from pymaven.errors import MissingArtifactError
+from pymaven.errors import MissingPathError
+
+try:
+    from unittest import mock
+except ImportError:
+    import mock
 
 
 class TestMavenClient(unittest.TestCase):
@@ -67,28 +71,44 @@ def test_find_artifacts(self, _LocalRepository):
 
     @mock.patch("pymaven.client.LocalRepository")
     def test_get_artifact(self, _LocalRepository):
-
         _repo = mock.Mock(spec=LocalRepository)
 
-        _repo.exists.side_effect = [True, False]
+        _repo.exists.side_effect = [True]
         _repo.open.return_value = StringIO("some data")
 
         _LocalRepository.return_value = _repo
 
         client = MavenClient("/maven")
-
         actual = client.get_artifact("foo:bar:2.0.0")
         assert "some data" == actual.contents.read()
         _repo.exists.assert_called_with("foo/bar/2.0.0/bar-2.0.0.jar")
         _repo.open.assert_called_with("foo/bar/2.0.0/bar-2.0.0.jar")
 
-        _repo.reset_mock()
+    @mock.patch("pymaven.client.LocalRepository")
+    def test_get_artifact_missing(self, _LocalRepository):
+        _repo = mock.Mock(spec=LocalRepository)
+
+        _repo.exists.side_effect = [False]
+        _repo.open.return_value = StringIO("some data")
+
+        _LocalRepository.return_value = _repo
+
+        client = MavenClient("/maven")
         self.assertRaises(MissingArtifactError, client.get_artifact,
                           "foo:bar:3.0")
         _repo.exists.assert_called_with("foo/bar/3.0/bar-3.0.jar")
         _repo.open.assert_not_called()
 
-        _repo.reset_mock()
+    @mock.patch("pymaven.client.LocalRepository")
+    def test_get_artifact_version_range(self, _LocalRepository):
+        _repo = mock.Mock(spec=LocalRepository)
+
+        _repo.exists.side_effect = [True, False]
+        _repo.open.return_value = StringIO("some data")
+
+        _LocalRepository.return_value = _repo
+
+        client = MavenClient("/maven")
         self.assertRaises(AssertionError, client.get_artifact,
                           "foo:bar:[1.0,2.0]")
         _repo.open.assert_not_called()
@@ -183,7 +203,7 @@ def test_get_versions(self, _os):
     def test_open(self):
         with tempfile.NamedTemporaryFile() as tmp:
             repo = LocalRepository(os.path.dirname(tmp.name))
-            tmp.write("the file\n")
+            tmp.write(b"the file\n")
             tmp.flush()
             with repo.open(tmp.name) as fh:
                 assert "the file\n" == fh.read()
diff --git a/tests/test_pom.py b/tests/test_pom.py
index d094074..f9e7a8a 100644
--- a/tests/test_pom.py
+++ b/tests/test_pom.py
@@ -15,17 +15,21 @@
 #
 
 
-from StringIO import StringIO
 import unittest
 
-import mock
+from six import StringIO
 
-from pymaven import Artifact
 from pymaven import VersionRange as VR
+from pymaven import Artifact
 from pymaven.client import MavenClient
 from pymaven.client import Struct
 from pymaven.pom import Pom
 
+try:
+    from unittest import mock
+except ImportError:
+    import mock
+
 
 class TestPom(unittest.TestCase):
 
diff --git a/tox.ini b/tox.ini
index 4f8504c..3e043cb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = clean, check, py{27,34,35,36}, report, docs
+envlist = clean, check, py{27,34,35,36}, report
 
 [testenv]
 setenv =
@@ -8,6 +8,7 @@ setenv =
 passenv =
     *
 deps =
+    -rrequirements.txt
     -rtest-requirements.txt
 commands =
     {posargs:py.test --cov --cov-report=term-missing -vv tests/}
@@ -38,14 +39,6 @@ commands =
     coverage xml --ignore-errors
     codecov []
 
-[testenv:docs]
-deps =
-    -r{toxinidir}/docs/requirements.txt
-commands =
-    sphinx-build {posargs:-E} -b doctest docs dist/docs
-    sphinx-build {posargs:-E} -b html docs dist/docs
-    sphinx-build -b linkcheck docs dist/docs
-
 [testenv:report]
 deps = coverage
 skip_install = true