TestCase: add aliases to assert methods on py3

The Python 2 assertItemsEqual() method was renamed to
assertCountEqual() in Python 3, and assertNotRegexpMatches() was
renamed to assertNotRegex(). Add aliases in
horizon.test.helpers.TestCase.

tox.ini: add horizon.test.tests.messages to Python 3.4.

Partial-Implements: blueprint porting-python3
Change-Id: If7abd51fd3559a5ab32d433c6dc3476bd678b2bf

horizon/test/helpers.py

@@ -35,6 +35,7 @@ from django.test.client import RequestFactory  # noqa
 from django.test import testcases
 from django.utils.encoding import force_text
 from django.utils import unittest
+import six
 
 if django.VERSION < (1, 7):
     from django.test import LiveServerTestCase  # noqa
@@ -169,6 +170,14 @@ class TestCase(django_test.TestCase):
         if hasattr(self.user, "_perm_cache"):
             del self.user._perm_cache
 
+    if six.PY3:
+        # Python 2 assert methods renamed in Python 3
+        def assertItemsEqual(self, expected_seq, actual_seq, msg=None):
+            self.assertCountEqual(expected_seq, actual_seq, msg)
+
+        def assertNotRegexpMatches(self, text, unexpected_regexp, msg=None):
+            self.assertNotRegex(text, unexpected_regexp, msg)
+
     def assertNoMessages(self, response=None):
         """Asserts that no messages have been attached by the
         ``contrib.messages`` framework.

tox.ini

@@ -24,6 +24,7 @@ commands =
     python manage.py test --settings=horizon.test.settings \
         horizon.test.tests.base \
         horizon.test.tests.forms \
+        horizon.test.tests.messages \
         horizon.test.tests.middleware \
         horizon.test.tests.tables.DataTableViewTests \
         horizon.test.tests.templatetags \