Create a utility testcase class that fixes some of the 2.6 missing pieces

- Add a helper testcase class that can add additional features into the
  unit test class as we need for features that are useful to have which
  starts with features that are missing including assertIn and assertNotIn

tests/unittests/helpers.py

@@ -1,4 +1,6 @@
 import os
+import sys
+import unittest
 
 from mocker import MockerTestCase
 
@@ -7,6 +9,27 @@ from cloudinit import util
 
 import shutil
 
+# Handle how 2.6 doesn't have the assertIn or assertNotIn
+_PY_VER = sys.version_info
+_PY_MAJOR, _PY_MINOR = _PY_VER[0:2]
+if (_PY_MAJOR, _PY_MINOR) <= (2, 6):
+    # For now add these on, taken from python 2.7 + slightly adjusted
+    class TestCase(unittest.TestCase):
+        def assertIn(self, member, container, msg=None):
+            if member not in container:
+                standardMsg = '%r not found in %r' % (member, container)
+                self.fail(self._formatMessage(msg, standardMsg))
+
+        def assertNotIn(self, member, container, msg=None):
+            if member in container:
+                standardMsg = '%r unexpectedly found in %r'
+                standardMsg = standardMsg % (member, container)
+                self.fail(self._formatMessage(msg, standardMsg))
+
+else:
+    class TestCase(unittest.TestCase):
+        pass
+
 
 # Makes the old path start
 # with new base instead of whatever

tests/unittests/test_handler/test_handler_power_state.py

@@ -1,9 +1,9 @@
-from unittest import TestCase
-
 from cloudinit.config import cc_power_state_change as psc
 
+from tests.unittests import helpers as t_help
 
-class TestLoadPowerState(TestCase):
+
+class TestLoadPowerState(t_help.TestCase):
     def setUp(self):
         super(self.__class__, self).setUp()