diff --git a/oslo_versionedobjects/tests/test_fields.py b/oslo_versionedobjects/tests/test_fields.py
index 1953788d..8ad1b38f 100644
--- a/oslo_versionedobjects/tests/test_fields.py
+++ b/oslo_versionedobjects/tests/test_fields.py
@@ -160,7 +160,7 @@ class TestString(TestField):
         self.coerce_good_values = [
             ('foo', 'foo'), (1, '1'), (1.0, '1.0'), (True, 'True')]
         if six.PY2:
-            self.coerce_good_values += [(long(1), '1')]
+            self.coerce_good_values += [(long(1), '1')]  # noqa
         self.coerce_bad_values = [None]
         self.to_primitive_values = self.coerce_good_values[0:1]
         self.from_primitive_values = self.coerce_good_values[0:1]
diff --git a/tox.ini b/tox.ini
index 3651b772..627a1fac 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,6 +3,7 @@ minversion = 2.0
 envlist = py35,py27,pep8
 
 [testenv]
+basepython = python3
 setenv =
     VIRTUAL_ENV={envdir}
     BRANCH_NAME=master
@@ -12,6 +13,9 @@ deps =
   -r{toxinidir}/test-requirements.txt
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
+[testenv:py27]
+basepython = python2.7
+
 [testenv:pep8]
 deps =
   -r{toxinidir}/test-requirements.txt
@@ -54,7 +58,6 @@ deps = -r{toxinidir}/doc/requirements.txt
 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