Adding revoke operation

kmip/core/enums.py

@@ -620,3 +620,12 @@ class ObjectGroupMember(Enum):
 class StorageStatusMask(Enum):
     ONLINE_STORAGE      = 0x00000001
     ARCHIVAL_STORAGE    = 0x00000002
+
+class RevocationReasonCode(Enum):
+    UNSPECIFIED            = 0x00000001
+    KEY_COMPROMISE         = 0x00000002
+    CA_COMPROMISE          = 0x00000003
+    AFFILIATION_CHANGED    = 0x00000004
+    SUPERSEDED             = 0x00000005
+    CESSATION_OF_OPERATION = 0x00000006
+    PRIVILEGE_WITHDRAWN    = 0x00000007

kmip/core/factories/payloads/request.py

@@ -25,6 +25,7 @@ from kmip.core.messages.payloads import locate
 from kmip.core.messages.payloads import query
 from kmip.core.messages.payloads import rekey_key_pair
 from kmip.core.messages.payloads import register
+from kmip.core.messages.payloads import revoke
 
 
 class RequestPayloadFactory(PayloadFactory):
@@ -58,3 +59,6 @@ class RequestPayloadFactory(PayloadFactory):
 
     def _create_activate_payload(self):
         return activate.ActivateRequestPayload()
+
+    def _create_revoke_payload(self):
+        return revoke.RevokeRequestPayload()

kmip/core/factories/payloads/response.py

@@ -25,6 +25,7 @@ from kmip.core.messages.payloads import locate
 from kmip.core.messages.payloads import query
 from kmip.core.messages.payloads import rekey_key_pair
 from kmip.core.messages.payloads import register
+from kmip.core.messages.payloads import revoke
 
 
 class ResponsePayloadFactory(PayloadFactory):
@@ -58,3 +59,6 @@ class ResponsePayloadFactory(PayloadFactory):
 
     def _create_activate_payload(self):
         return activate.ActivateResponsePayload()
+
+    def _create_revoke_payload(self):
+        return revoke.RevokeResponsePayload()

kmip/core/messages/payloads/revoke.py

@@ -0,0 +1,193 @@
+# Copyright (c) 2015 Hewlett Packard Development Company, L.P.
+# All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from kmip.core import attributes
+from kmip.core import enums
+from kmip.core import objects
+from kmip.core import primitives
+
+from kmip.core.primitives import Struct
+
+from kmip.core.utils import BytearrayStream
+
+
+class RevokeRequestPayload(Struct):
+    """
+    A request payload for the Revoke operation.
+
+    The payload contains a UUID of a cryptographic object that that server
+    should revoke. See Section 4.20 of the KMIP 1.1 specification for more
+    information.
+
+    Attributes:
+        unique_identifier: The UUID of a managed cryptographic object
+        revocation_reason: The reason why the object was revoked
+        compromised_date: The date of compromise if the object was compromised
+    """
+
+    def __init__(self,
+                 unique_identifier=None,
+                 revocation_reason=None,
+                 compromise_date=None):
+        """
+        Construct a RevokeRequestPayload object.
+        Args:
+            unique_identifier (UniqueIdentifier): The UUID of a managed
+                cryptographic object.
+            revocation_reason (RevocationReason): The reason why the object was
+                revoked.
+            compromise_date (DateTime): the date of compromise if the object
+                was compromised.
+        """
+        super(RevokeRequestPayload, self).__init__(
+            tag=enums.Tags.REQUEST_PAYLOAD)
+        self.unique_identifier = unique_identifier
+        self.compromise_date = compromise_date
+        self.revocation_reason = revocation_reason
+        if self.revocation_reason is None:
+            self.revocation_reason = objects.RevocationReason()
+        self.validate()
+
+    def read(self, istream):
+        """
+        Read the data encoding the RevokeRequestPayload object and decode it
+        into its constituent parts.
+        Args:
+            istream (Stream): A data stream containing encoded object data,
+                supporting a read method; usually a BytearrayStream object.
+        """
+        super(RevokeRequestPayload, self).read(istream)
+        tstream = BytearrayStream(istream.read(self.length))
+
+        self.unique_identifier = attributes.UniqueIdentifier()
+        self.unique_identifier.read(tstream)
+
+        self.revocation_reason = objects.RevocationReason()
+        self.revocation_reason.read(tstream)
+
+        if self.is_tag_next(enums.Tags.COMPROMISE_OCCURRENCE_DATE, tstream):
+            self.compromise_date = primitives.DateTime(
+                tag=enums.Tags.COMPROMISE_OCCURRENCE_DATE)
+            self.compromise_date.read(tstream)
+
+        self.is_oversized(tstream)
+        self.validate()
+
+    def write(self, ostream):
+        """
+        Write the data encoding the RevokeRequestPayload object to a stream.
+        Args:
+            ostream (Stream): A data stream in which to encode object data,
+                supporting a write method; usually a BytearrayStream object.
+        """
+        tstream = BytearrayStream()
+
+        # Write the contents of the request payload
+        if self.unique_identifier is not None:
+            self.unique_identifier.write(tstream)
+
+        self.revocation_reason.write(tstream)
+
+        if self.compromise_date is not None:
+            self.compromise_date.write(tstream)
+
+        # Write the length and value of the request payload
+        self.length = tstream.length()
+        super(RevokeRequestPayload, self).write(ostream)
+        ostream.write(tstream.buffer)
+
+    def validate(self):
+        """
+        Error check the attributes of the ActivateRequestPayload object.
+        """
+        if self.unique_identifier is not None:
+            if not isinstance(self.unique_identifier,
+                              attributes.UniqueIdentifier):
+                msg = "invalid unique identifier"
+                raise TypeError(msg)
+        if self.compromise_date is not None:
+            if not isinstance(self.compromise_date, primitives.DateTime):
+                msg = "invalid compromise time"
+                raise TypeError(msg)
+        if not isinstance(self.revocation_reason, objects.RevocationReason):
+            msg = "invalid revocation reason"
+            raise TypeError(msg)
+
+
+class RevokeResponsePayload(Struct):
+    """
+    A response payload for the Revoke operation.
+    The payload contains the server response to the initial Revoke request.
+    See Section 4.20 of the KMIP 1.1 specification for more information.
+    Attributes:
+        unique_identifier: The UUID of a managed cryptographic object.
+    """
+    def __init__(self,
+                 unique_identifier=None):
+        """
+        Construct a RevokeResponsePayload object.
+        Args:
+            unique_identifier (UniqueIdentifier): The UUID of a managed
+                cryptographic object.
+        """
+        super(RevokeResponsePayload, self).__init__(
+            tag=enums.Tags.RESPONSE_PAYLOAD)
+        if unique_identifier is None:
+            self.unique_identifier = attributes.UniqueIdentifier()
+        else:
+            self.unique_identifier = unique_identifier
+        self.validate()
+
+    def read(self, istream):
+        """
+        Read the data encoding the RevokeResponsePayload object and decode it
+        into its constituent parts.
+        Args:
+            istream (Stream): A data stream containing encoded object data,
+                supporting a read method; usually a BytearrayStream object.
+        """
+        super(RevokeResponsePayload, self).read(istream)
+        tstream = BytearrayStream(istream.read(self.length))
+
+        self.unique_identifier = attributes.UniqueIdentifier()
+        self.unique_identifier.read(tstream)
+
+        self.is_oversized(tstream)
+        self.validate()
+
+    def write(self, ostream):
+        """
+        Write the data encoding the RevokeResponsePayload object to a stream.
+        Args:
+            ostream (Stream): A data stream in which to encode object data,
+                supporting a write method; usually a BytearrayStream object.
+        """
+        tstream = BytearrayStream()
+
+        # Write the contents of the response payload
+        self.unique_identifier.write(tstream)
+
+        # Write the length and value of the request payload
+        self.length = tstream.length()
+        super(RevokeResponsePayload, self).write(ostream)
+        ostream.write(tstream.buffer)
+
+    def validate(self):
+        """
+        Error check the attributes of the RevokeRequestPayload object.
+        """
+        if not isinstance(self.unique_identifier, attributes.UniqueIdentifier):
+            msg = "invalid unique identifier"
+            raise TypeError(msg)

kmip/core/objects.py

@@ -25,6 +25,7 @@ from kmip.core.enums import AttributeType
 from kmip.core.enums import Tags
 from kmip.core.enums import Types
 from kmip.core.enums import CredentialType
+from kmip.core.enums import RevocationReasonCode as RevocationReasonCodeEnum
 
 from kmip.core.errors import ErrorStrings
 from kmip.core.misc import KeyFormatType
@@ -1177,3 +1178,102 @@ class ExtensionInformation(Struct):
             extension_name=extension_name,
             extension_tag=extension_tag,
             extension_type=extension_type)
+
+
+# 3.31, 9.1.3.2.19
+class RevocationReasonCode(Enumeration):
+    ENUM_TYPE = RevocationReasonCodeEnum
+
+    def __init__(self, value=RevocationReasonCodeEnum.UNSPECIFIED):
+        super(RevocationReasonCode, self).__init__(
+            value=value, tag=Tags.REVOCATION_REASON_CODE)
+
+
+# 3.31
+class RevocationReason(Struct):
+    """
+    A structure describing  the reason for a revocation operation.
+
+    See Sections 2.1.9 and 4.25 of the KMIP 1.1 specification for
+    more information.
+
+    Attributes:
+        code: The revocation reason code enumeration
+        message: An optional revocation message
+    """
+
+    def __init__(self, code=None, message=None):
+        """
+        Construct a RevocationReason object.
+
+        Parameters:
+            code(RevocationReasonCode): revocation reason code
+            message(string): An optional revocation message
+        """
+        super(RevocationReason, self).__init__(tag=Tags.REVOCATION_REASON)
+        if code is not None:
+            self.revocation_code = RevocationReasonCode(value=code)
+        else:
+            self.revocation_code = RevocationReasonCode()
+
+        if message is not None:
+            self.revocation_message = TextString(
+                value=message,
+                tag=Tags.REVOCATION_MESSAGE)
+        else:
+            self.revocation_message = None
+
+        self.validate()
+
+    def read(self, istream):
+        """
+        Read the data encoding the RevocationReason object and decode it
+        into its constituent parts.
+
+        Args:
+            istream (Stream): A data stream containing encoded object data,
+                supporting a read method; usually a BytearrayStream object.
+        """
+        super(RevocationReason, self).read(istream)
+        tstream = BytearrayStream(istream.read(self.length))
+
+        self.revocation_code = RevocationReasonCode()
+        self.revocation_code.read(tstream)
+
+        if self.is_tag_next(Tags.REVOCATION_MESSAGE, tstream):
+            self.revocation_message = TextString()
+            self.revocation_message.read(tstream)
+
+        self.is_oversized(tstream)
+        self.validate()
+
+    def write(self, ostream):
+        """
+        Write the data encoding the RevocationReason object to a stream.
+
+        Args:
+            ostream (Stream): A data stream in which to encode object data,
+                supporting a write method; usually a BytearrayStream object.
+        """
+        tstream = BytearrayStream()
+
+        self.revocation_code.write(tstream)
+        if self.revocation_message is not None:
+            self.revocation_message.write(tstream)
+
+        # Write the length and value
+        self.length = tstream.length()
+        super(RevocationReason, self).write(ostream)
+        ostream.write(tstream.buffer)
+
+    def validate(self):
+        """
+        validate the RevocationReason object
+        """
+        if not isinstance(self.revocation_code, RevocationReasonCode):
+            msg = "RevocationReaonCode expected"
+            raise TypeError(msg)
+        if self.revocation_message is not None:
+            if not isinstance(self.revocation_message, TextString):
+                msg = "TextString expect"
+                raise TypeError(msg)

kmip/services/kmip_client.py

@@ -23,6 +23,7 @@ from kmip.services.results import LocateResult
 from kmip.services.results import QueryResult
 from kmip.services.results import RegisterResult
 from kmip.services.results import RekeyKeyPairResult
+from kmip.services.results import RevokeResult
 
 from kmip.core import attributes as attr
 
@@ -53,6 +54,7 @@ from kmip.core.messages.payloads import locate
 from kmip.core.messages.payloads import query
 from kmip.core.messages.payloads import rekey_key_pair
 from kmip.core.messages.payloads import register
+from kmip.core.messages.payloads import revoke
 
 from kmip.services.kmip_protocol import KMIPProtocol
 
@@ -263,6 +265,12 @@ class KMIPProxy(KMIP):
             key_wrapping_specification=key_wrapping_specification,
             credential=credential)
 
+    def revoke(self, uuid, reason, message=None, credential=None):
+        return self._revoke(unique_identifier=uuid,
+                            revocation_code=reason,
+                            revocation_message=message,
+                            credential=credential)
+
     def destroy(self, uuid, credential=None):
         return self._destroy(unique_identifier=uuid,
                              credential=credential)
@@ -631,6 +639,43 @@ class KMIPProxy(KMIP):
                                payload_unique_identifier)
         return result
 
+    def _revoke(self, unique_identifier=None, revocation_code=None,
+                revocation_message=None, credential=None):
+        operation = Operation(OperationEnum.REVOKE)
+
+        reason = objects.RevocationReason(code=revocation_code,
+                                          message=revocation_message)
+        uuid = None
+        if unique_identifier is not None:
+            uuid = attr.UniqueIdentifier(unique_identifier)
+
+        payload = revoke.RevokeRequestPayload(
+            unique_identifier=uuid,
+            revocation_reason=reason,
+            compromise_date=None)  # TODO(tim-kelsey): sort out date handling
+
+        batch_item = messages.RequestBatchItem(operation=operation,
+                                               request_payload=payload)
+        message = self._build_request_message(credential, [batch_item])
+        self._send_message(message)
+        message = messages.ResponseMessage()
+        data = self._receive_message()
+        message.read(data)
+        batch_items = message.batch_items
+        batch_item = batch_items[0]
+        payload = batch_item.response_payload
+
+        if payload is None:
+            payload_unique_identifier = None
+        else:
+            payload_unique_identifier = payload.unique_identifier
+
+        result = RevokeResult(batch_item.result_status,
+                              batch_item.result_reason,
+                              batch_item.result_message,
+                              payload_unique_identifier)
+        return result
+
     def _register(self,
                   object_type=None,
                   template_attribute=None,

kmip/services/results.py

@@ -249,3 +249,15 @@ class DiscoverVersionsResult(OperationResult):
         super(DiscoverVersionsResult, self).__init__(
             result_status, result_reason, result_message)
         self.protocol_versions = protocol_versions
+
+
+class RevokeResult(OperationResult):
+
+    def __init__(self,
+                 result_status,
+                 result_reason=None,
+                 result_message=None,
+                 unique_identifier=None):
+        super(RevokeResult, self).__init__(
+            result_status, result_reason, result_message)
+        self.unique_identifier = unique_identifier

kmip/tests/unit/core/factories/payloads/test_request.py

@@ -28,6 +28,7 @@ from kmip.core.messages.payloads import locate
 from kmip.core.messages.payloads import query
 from kmip.core.messages.payloads import rekey_key_pair
 from kmip.core.messages.payloads import register
+from kmip.core.messages.payloads import revoke
 
 
 class TestRequestPayloadFactory(testtools.TestCase):
@@ -120,8 +121,8 @@ class TestRequestPayloadFactory(testtools.TestCase):
         self._test_payload_type(payload, activate.ActivateRequestPayload)
 
     def test_create_revoke_payload(self):
-        self._test_not_implemented(
+        payload = self.factory.create(Operation.REVOKE)
-            self.factory.create, Operation.REVOKE)
+        self._test_payload_type(payload, revoke.RevokeRequestPayload)
 
     def test_create_destroy_payload(self):
         payload = self.factory.create(Operation.DESTROY)

kmip/tests/unit/core/factories/payloads/test_response.py

@@ -28,6 +28,7 @@ from kmip.core.messages.payloads import locate
 from kmip.core.messages.payloads import query
 from kmip.core.messages.payloads import rekey_key_pair
 from kmip.core.messages.payloads import register
+from kmip.core.messages.payloads import revoke
 
 
 class TestResponsePayloadFactory(testtools.TestCase):
@@ -120,8 +121,8 @@ class TestResponsePayloadFactory(testtools.TestCase):
         self._test_payload_type(payload, activate.ActivateResponsePayload)
 
     def test_create_revoke_payload(self):
-        self._test_not_implemented(
+        payload = self.factory.create(Operation.REVOKE)
-            self.factory.create, Operation.REVOKE)
+        self._test_payload_type(payload, revoke.RevokeResponsePayload)
 
     def test_create_destroy_payload(self):
         payload = self.factory.create(Operation.DESTROY)

kmip/tests/unit/core/messages/payloads/test_revoke.py

@@ -0,0 +1,222 @@
+# Copyright (c) 2015 Hewlett Packard Development Company, L.P.
+# All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from testtools import TestCase
+
+from kmip.core import attributes
+from kmip.core import enums
+from kmip.core import objects
+from kmip.core import primitives
+from kmip.core import utils
+
+from kmip.core.messages.payloads import revoke
+
+
+class TestRevokeRequestPayload(TestCase):
+    """
+    Test suite for the RevokeRequestPayload class.
+
+    Test encodings obtained from Sections 4.2 of the KMIP 1.1 Test
+    Cases documentation.
+    """
+
+    def setUp(self):
+        super(TestRevokeRequestPayload, self).setUp()
+
+        self.uuid = attributes.UniqueIdentifier(
+            '668eff89-3010-4258-bc0e-8c402309c746')
+
+        self.encoding_a = utils.BytearrayStream((
+            b'\x42\x00\x79\x01\x00\x00\x00\x58\x42\x00\x94\x07\x00\x00\x00\x24'
+            b'\x36\x36\x38\x65\x66\x66\x38\x39\x2D\x33\x30\x31\x30\x2D\x34\x32'
+            b'\x35\x38\x2D\x62\x63\x30\x65\x2D\x38\x63\x34\x30\x32\x33\x30\x39'
+            b'\x63\x37\x34\x36\x00\x00\x00\x00\x42\x00\x81\x01\x00\x00\x00\x10'
+            b'\x42\x00\x82\x05\x00\x00\x00\x04\x00\x00\x00\x02\x00\x00\x00\x00'
+            b'\x42\x00\x21\x09\x00\x00\x00\x08\x00\x00\x00\x00\x00\x00\x00\x06'
+            ))
+
+    def tearDown(self):
+        super(TestRevokeRequestPayload, self).tearDown()
+
+    def test_init_with_none(self):
+        """
+        Test that a RevokeRequestPayload object can be constructed with no
+        specified value.
+        """
+        revoke.RevokeRequestPayload()
+
+    def test_init_with_args(self):
+        """
+        Test that a RevokeRequestPayload object can be constructed with valid
+        values.
+        """
+        revoke.RevokeRequestPayload(unique_identifier=self.uuid)
+
+    def test_validate_with_bad_uuid_type(self):
+        """
+        Test that a TypeError exception is raised when an invalid UUID type
+        is used to construct a RevokeRequestPayload object.
+        """
+        self.assertRaisesRegexp(
+            TypeError, "invalid unique identifier",
+            revoke.RevokeRequestPayload, "not-a-uuid")
+
+    def test_validate_with_bad_date_type(self):
+        """
+        Test that a TypeError exception is raised when an invalid UUID type
+        is used to construct a RevokeRequestPayload object.
+        """
+        reason = objects.RevocationReason()
+        self.assertRaisesRegexp(
+            TypeError, "invalid compromise time",
+            revoke.RevokeRequestPayload, self.uuid, reason, "not-a-date")
+
+    def test_validate_with_bad_reason_type(self):
+        """
+        Test that a TypeError exception is raised when an invalid UUID type
+        is used to construct a RevokeRequestPayload object.
+        """
+        self.assertRaisesRegexp(
+            TypeError, "invalid revocation reason",
+            revoke.RevokeRequestPayload, self.uuid, "not-a-reason")
+
+    def test_read_with_known_uuid(self):
+        """
+        Test that a RevokeRequestPayload object with known UUID can be read
+        from a data stream.
+        """
+        payload = revoke.RevokeRequestPayload()
+        payload.read(self.encoding_a)
+        expected = '668eff89-3010-4258-bc0e-8c402309c746'
+        observed = payload.unique_identifier.value
+
+        msg = "Revoke UUID value mismatch"
+        msg += "; expected {0}, received {1}".format(
+            expected, observed)
+        self.assertEqual(expected, observed, msg)
+
+    def test_write_with_known_uuid(self):
+        """
+        Test that a RevokeRequestPayload object with a known UUID can be
+        written to a data stream.
+        """
+        reason = objects.RevocationReason(
+            code=enums.RevocationReasonCode.KEY_COMPROMISE)
+        date = primitives.DateTime(
+            tag=enums.Tags.COMPROMISE_OCCURRENCE_DATE, value=6)
+
+        stream = utils.BytearrayStream()
+        payload = revoke.RevokeRequestPayload(
+            unique_identifier=self.uuid,
+            revocation_reason=reason,
+            compromise_date=date)
+        payload.write(stream)
+
+        length_expected = len(self.encoding_a)
+        length_received = len(stream)
+
+        msg = "encoding lengths not equal"
+        msg += "; expected {0}, received {1}".format(
+            length_expected, length_received)
+        self.assertEqual(length_expected, length_received, msg)
+
+        msg = "encoding mismatch"
+        msg += ";\nexpected:\n{0}\nreceived:\n{1}".format(self.encoding_a,
+                                                          stream)
+
+        self.assertEqual(self.encoding_a, stream, msg)
+
+
+class TestRevokeResponsePayload(TestCase):
+    """
+    Test encodings obtained from Sections 4.2 of the KMIP 1.1 Test
+    Cases documentation.
+    """
+
+    def setUp(self):
+        super(TestRevokeResponsePayload, self).setUp()
+
+        self.uuid = attributes.UniqueIdentifier(
+            '668eff89-3010-4258-bc0e-8c402309c746')
+
+        self.encoding_a = utils.BytearrayStream((
+            b'\x42\x00\x7C\x01\x00\x00\x00\x30\x42\x00\x94\x07\x00\x00\x00\x24'
+            b'\x36\x36\x38\x65\x66\x66\x38\x39\x2D\x33\x30\x31\x30\x2D\x34\x32'
+            b'\x35\x38\x2D\x62\x63\x30\x65\x2D\x38\x63\x34\x30\x32\x33\x30\x39'
+            b'\x63\x37\x34\x36\x00\x00\x00\x00'))
+
+    def tearDown(self):
+        super(TestRevokeResponsePayload, self).tearDown()
+
+    def test_init_with_none(self):
+        """
+        Test that a RevokeResponsePayload object can be constructed with no
+        specified value.
+        """
+        revoke.RevokeResponsePayload()
+
+    def test_init_with_args(self):
+        """
+        Test that a RevokeResponsePayload object can be constructed with
+        valid values.
+        """
+        revoke.RevokeResponsePayload(unique_identifier=self.uuid)
+
+    def test_validate_with_invalid_uuid(self):
+        """
+        Test that a TypeError exception is raised when an invalid Operations
+        list is used to construct a RevokeResponsePayload object.
+        """
+        self.assertRaisesRegexp(
+            TypeError, "invalid unique identifier",
+            revoke.RevokeResponsePayload, "not-a-uuid")
+
+    def test_read_with_known_uuid(self):
+        """
+        Test that a RevokeResponsePayload object with known UUID can be read
+        from a data stream.
+        """
+        payload = revoke.RevokeResponsePayload()
+        payload.read(self.encoding_a)
+        expected = '668eff89-3010-4258-bc0e-8c402309c746'
+        observed = payload.unique_identifier.value
+
+        msg = "Revoke UUID value mismatch"
+        msg += "; expected {0}, received {1}".format(
+            expected, observed)
+        self.assertEqual(expected, observed, msg)
+
+    def test_write_with_known_uuid(self):
+        """
+        Test that a RevokeResponsePayload object with a known UUID can be
+        written to a data stream.
+        """
+        stream = utils.BytearrayStream()
+        payload = revoke.RevokeResponsePayload(self.uuid)
+        payload.write(stream)
+
+        length_expected = len(self.encoding_a)
+        length_received = len(stream)
+
+        msg = "encoding lengths not equal"
+        msg += "; expected {0}, received {1}".format(
+            length_expected, length_received)
+        self.assertEqual(length_expected, length_received, msg)
+
+        msg = "encoding mismatch"
+        msg += ";\nexpected:\n{0}\nreceived:\n{1}".format(self.encoding_a,
+                                                          stream)
+
+        self.assertEqual(self.encoding_a, stream, msg)