Add SetAttribute support to the client

This change adds SetAttribute support to the ProxyKmipClient,
leveraging the new generic request capability in the underlying
KMIPProxy client. New unit tests have been added to cover the new
client additions.

Partially implements #547

kmip/pie/client.py

@@ -102,6 +102,7 @@ class ProxyKmipClient(object):
         self.logger = logging.getLogger(__name__)
 
         self.attribute_factory = attributes.AttributeFactory()
+        self.attribute_value_factory = self.attribute_factory.value_factory
         self.object_factory = factory.ObjectFactory()
 
         # TODO (peter-hamilton) Consider adding validation checks for inputs.
@@ -431,6 +432,46 @@ class ProxyKmipClient(object):
 
         return response_payload.unique_identifier, response_payload.attribute
 
+    @is_connected
+    def set_attribute(self, unique_identifier=None, **kwargs):
+        """
+        Set an attribute on a KMIP managed object.
+
+        Args:
+            unique_identifier (string): The ID of the managed object.
+            **kwargs (various): A placeholder for attribute-related fields.
+                Supported parameters include:
+                    attribute_name (string): The name of the attribute being
+                        set. Required.
+                    attribute_value (various): The value of the attribute
+                        being set. Required.
+
+                Here is an example. To set an object's 'sensitive' attribute
+                to True, specify:
+                    attribute_name='Sensitive'
+                    attribute_value=True
+
+                For a list of all supported attributes, see the
+                AttributeValueFactory.
+
+        Returns:
+            string: The ID of the managed object the attribute was set on.
+        """
+        a = self.attribute_value_factory.create_attribute_value_by_enum(
+            enums.convert_attribute_name_to_tag(kwargs.get("attribute_name")),
+            kwargs.get("attribute_value")
+        )
+        request_payload = payloads.SetAttributeRequestPayload(
+            unique_identifier=unique_identifier,
+            new_attribute=cobjects.NewAttribute(attribute=a)
+        )
+        response_payload = self.proxy.send_request_payload(
+            enums.Operation.SET_ATTRIBUTE,
+            request_payload
+        )
+
+        return response_payload.unique_identifier
+
     @is_connected
     def register(self, managed_object):
         """