diff --git a/oslo_i18n/tests/test_factory.py b/oslo_i18n/tests/test_factory.py
index 8a3599d..6bbe684 100644
--- a/oslo_i18n/tests/test_factory.py
+++ b/oslo_i18n/tests/test_factory.py
@@ -59,8 +59,7 @@ class TranslatorFactoryTest(test_base.BaseTestCase):
         self.assertIsInstance(r, _message.Message)
         _lazy.enable_lazy(False)
         r = tf.primary('some text')
-        # Python 2.6 doesn't have assertNotIsInstance().
-        self.assertFalse(isinstance(r, _message.Message))
+        self.assertNotIsInstance(r, _message.Message)
 
     def test_py2(self):
         _lazy.enable_lazy(False)
diff --git a/oslo_i18n/tests/test_fixture.py b/oslo_i18n/tests/test_fixture.py
index db67033..8ea9a1c 100644
--- a/oslo_i18n/tests/test_fixture.py
+++ b/oslo_i18n/tests/test_fixture.py
@@ -37,8 +37,7 @@ class TranslationFixtureTest(test_base.BaseTestCase):
 
     def test_immediate(self):
         msg = self.trans_fixture.immediate('this is a lazy message')
-        # Python 2.6 does not have assertNotIsInstance
-        self.assertFalse(isinstance(msg, _message.Message))
+        self.assertNotIsInstance(msg, _message.Message)
         self.assertIsInstance(msg, six.text_type)
         self.assertEqual(msg, u'this is a lazy message')