Support Python 3 using six

tests/helpers.py

@@ -1,5 +1,6 @@
 from __future__ import unicode_literals
 import boto
+import six
 from nose.plugins.skip import SkipTest
 
 
@@ -18,3 +19,19 @@ class requires_boto_gte(object):
         if boto_version >= required:
             return test
         raise SkipTest
+
+
+class py3_requires_boto_gte(object):
+    """Decorator for requiring boto version greater than or equal to 'version'
+    when running on Python 3. (Not all of boto is Python 3 compatible.)"""
+    def __init__(self, version):
+        self.version = version
+
+    def __call__(self, test):
+        if not six.PY3:
+            return test
+        boto_version = version_tuple(boto.__version__)
+        required = version_tuple(self.version)
+        if boto_version >= required:
+            return test
+        raise SkipTest