diff --git a/oslo_vmware/tests/test_service.py b/oslo_vmware/tests/test_service.py
index 336ef0d0..e20f96dd 100644
--- a/oslo_vmware/tests/test_service.py
+++ b/oslo_vmware/tests/test_service.py
@@ -13,6 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import io
+
 import mock
 import requests
 import six
@@ -500,16 +502,12 @@ class RequestsTransportTest(base.TestCase):
 
         if six.PY3:
             builtin_open = 'builtins.open'
-            open_mock = mock.MagicMock(name='file_handle',
-                                       spec=open)
-            import _io
-            file_spec = list(set(dir(_io.TextIOWrapper)).union(
-                set(dir(_io.BytesIO))))
         else:
             builtin_open = '__builtin__.open'
-            open_mock = mock.MagicMock(name='file_handle',
-                                       spec=file)
-            file_spec = file
+        open_mock = mock.MagicMock(name='file_handle',
+                                   spec=open)
+        file_spec = list(set(dir(io.TextIOWrapper)).union(
+            set(dir(io.BytesIO))))
 
         file_handle = mock.MagicMock(spec=file_spec)
         file_handle.write.return_value = None
diff --git a/tox.ini b/tox.ini
index 795d7f15..cd87fe97 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,6 +3,7 @@ minversion = 2.0
 envlist = py35,py27,pep8
 
 [testenv]
+basepython = python3
 install_command = pip install {opts} {packages}
 whitelist_externals = find
                       rm
@@ -12,6 +13,9 @@ deps =
   -r{toxinidir}/requirements.txt
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
+[testenv:py27]
+basepython = python2.7
+
 [testenv:pep8]
 commands =
   flake8
@@ -64,7 +68,6 @@ commands = pip-missing-reqs -d --ignore-module=oslo_vmware* --ignore-file=oslo_v
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:lower-constraints]
-basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt