Adding support for the State attribute

This change adds the State attribute, updating the attribute
factory to support creating it.

kmip/core/attributes.py

@@ -620,6 +620,12 @@ class CryptographicUsageMask(Integer):
             value, Tags.CRYPTOGRAPHIC_USAGE_MASK)
 
 
+class State(Enumeration):
+
+    def __init__(self, value=None):
+        super(State, self).__init__(enums.State, value, Tags.STATE)
+
+
 # 3.33
 class ObjectGroup(TextString):
 

kmip/core/factories/attribute_values.py

@@ -66,7 +66,7 @@ class AttributeValueFactory(object):
         elif name is enums.AttributeType.USAGE_LIMITS:
             raise NotImplementedError()
         elif name is enums.AttributeType.STATE:
-            raise NotImplementedError()
+            return attributes.State(value)
         elif name is enums.AttributeType.INITIAL_DATE:
             return primitives.DateTime(value, enums.Tags.INITIAL_DATE)
         elif name is enums.AttributeType.ACTIVATION_DATE:

kmip/tests/unit/core/factories/test_attribute_values.py

@@ -228,10 +228,12 @@ class TestAttributeValueFactory(testtools.TestCase):
         """
         Test that a State attribute can be created.
         """
-        kwargs = {'name': enums.AttributeType.STATE,
-                  'value': None}
-        self.assertRaises(
-            NotImplementedError, self.factory.create_attribute_value, **kwargs)
+        state = self.factory.create_attribute_value(
+            enums.AttributeType.STATE,
+            enums.State.ACTIVE
+        )
+        self.assertIsInstance(state, attributes.State)
+        self.assertEqual(enums.State.ACTIVE, state.value)
 
     def test_create_initial_date(self):
         """