Fixed the __ne__ implementation in base.Resource

Any object of Resource class or its child class do not compare with
None as expected. For example if a server has been found and is
clearly not None, the test "server!=None" will be False.

This was occuring because the __eq__ implementation was returning the
'NotImplemented' keyword and the __ne__ implementation was returning
the not of __eq__, which in this case will return False as the
expected python behavior for a the not of NotImplemented is False.

Changed the __ne__ implementation to return the correct boolean value
and added the test case that fails with the older implementation and
passes in the current fix.

Change-Id: I6bf5a6e9c9eed4bbcf6678467df19dfea560b4de
Closes-Bug: #1648207

novaclient/base.py

@@ -210,7 +210,9 @@ class Resource(RequestIdMixin):
         return self._info == other._info
 
     def __ne__(self, other):
-        return not self.__eq__(other)
+        # Using not of '==' implementation because the not of
+        # __eq__, when it returns NotImplemented, is returning False.
+        return not self == other
 
     def is_loaded(self):
         return self._loaded

novaclient/tests/unit/test_base.py

@@ -71,6 +71,12 @@ class BaseTest(utils.TestCase):
         r2 = base.Resource(None, {'name': 'joe', 'age': 12})
         self.assertEqual(r1, r2)
 
+    def test_ne(self):
+        # Two resources of different types: never equal
+        r1 = base.Resource(None, {'id': 1, 'name': 'test'})
+        r2 = object()
+        self.assertNotEqual(r1, r2)
+
     def test_findall_invalid_attribute(self):
         cs = fakes.FakeClient(api_versions.APIVersion("2.0"))
         # Make sure findall with an invalid attribute doesn't cause errors.