Add __ne__ built-in function

In Python 3 __ne__ by default delegates to __eq__ and inverts the
result, but in Python 2 they urge you to define __ne__ when you define
__eq__ for it to work properly [1]. There are no implied relationships
among the comparison operators. The truth of x==y does not imply that
x!=y is false. Accordingly, when defining __eq__(), one should also
define __ne__() so that the operators will behave as expected.

[1]https://docs.python.org/2/reference/datamodel.html#object.__ne__

Change-Id: I6ad4b07911f6c8236dfcd048aceebd44cd760fe2

keystoneauth1/loading/opts.py

@@ -125,6 +125,12 @@ class Opt(object):
                 self.default == other.default and
                 self.metavar == other.metavar)
 
+    # NOTE: This function is only needed by Python 2. If we get to point where
+    # we don't support Python 2 anymore, this function should be removed.
+    def __ne__(self, other):
+        """Define inequality operator on option parameters."""
+        return not self.__eq__(other)
+
     @property
     def _all_opts(self):
         return itertools.chain([self], self.deprecated)

keystoneauth1/tests/unit/loading/utils.py

@@ -76,6 +76,12 @@ class BoolType(object):
         # hack around oslo.config equality comparison
         return type(self) == type(other)
 
+    # NOTE: This function is only needed by Python 2. If we get to point where
+    # we don't support Python 2 anymore, this function should be removed.
+    def __ne__(self, other):
+        """Define inequiality for many bool types."""
+        return not self.__eq__(other)
+
     def __call__(self, value):
         return str(value).lower() in ('1', 'true', 't', 'yes', 'y')
 

keystoneauth1/tests/unit/utils.py

@@ -135,6 +135,12 @@ class TestResponse(requests.Response):
         """Define equiality behavior of request and response."""
         return self.__dict__ == other.__dict__
 
+    # NOTE: This function is only needed by Python 2. If we get to point where
+    # we don't support Python 2 anymore, this function should be removed.
+    def __ne__(self, other):
+        """Define inequiality behavior of request and response."""
+        return not self.__eq__(other)
+
     @property
     def text(self):
         return self.content