diff --git a/releasenotes/notes/add-image-clients-tests-49dbc0a0a4281a77.yaml b/releasenotes/notes/add-image-clients-tests-49dbc0a0a4281a77.yaml
new file mode 100644
index 0000000..9d1a003
--- /dev/null
+++ b/releasenotes/notes/add-image-clients-tests-49dbc0a0a4281a77.yaml
@@ -0,0 +1,9 @@
+---
+features:
+  - |
+    As in the [doc]:
+    http://developer.openstack.org/api-ref/image/v2/metadefs-index.html,
+    there are some apis are not included, add them.
+
+      * namespace_objects_client(v2)
+
diff --git a/tempest/api/image/base.py b/tempest/api/image/base.py
index 812c436..23bd628 100644
--- a/tempest/api/image/base.py
+++ b/tempest/api/image/base.py
@@ -142,6 +142,7 @@
         cls.namespaces_client = cls.os.namespaces_client
         cls.resource_types_client = cls.os.resource_types_client
         cls.namespace_properties_client = cls.os.namespace_properties_client
+        cls.namespace_objects_client = cls.os.namespace_objects_client
         cls.schemas_client = cls.os.schemas_client
 
     def create_namespace(cls, namespace_name=None, visibility='public',
diff --git a/tempest/api/image/v2/test_images_metadefs_namespace_objects.py b/tempest/api/image/v2/test_images_metadefs_namespace_objects.py
new file mode 100644
index 0000000..95d1521
--- /dev/null
+++ b/tempest/api/image/v2/test_images_metadefs_namespace_objects.py
@@ -0,0 +1,73 @@
+#    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 tempest.api.image import base
+from tempest.common.utils import data_utils
+from tempest.lib.common.utils import test_utils
+from tempest import test
+
+
+class MetadataNamespaceObjectsTest(base.BaseV2ImageTest):
+    """Test the Metadata definition namespace objects basic functionality"""
+
+    def _create_namespace_object(self, namespace):
+        object_name = data_utils.rand_name(self.__class__.__name__ + '-object')
+        namespace_object = self.namespace_objects_client.\
+            create_namespace_object(namespace['namespace'], name=object_name)
+        self.addCleanup(test_utils.call_and_ignore_notfound_exc,
+                        self.namespace_objects_client.delete_namespace_object,
+                        namespace['namespace'], object_name)
+        return namespace_object
+
+    @test.idempotent_id('b1a3775e-3b5c-4f6a-a3b4-1ba3574ae718')
+    def test_create_update_delete_meta_namespace_objects(self):
+        # Create a namespace
+        namespace = self.create_namespace()
+        # Create a namespace object
+        body = self._create_namespace_object(namespace)
+        # Update a namespace object
+        up_object_name = data_utils.rand_name('update-object')
+        body = self.namespace_objects_client.update_namespace_object(
+            namespace['namespace'], body['name'],
+            name=up_object_name)
+        self.assertEqual(up_object_name, body['name'])
+        # Delete a namespace object
+        self.namespace_objects_client.delete_namespace_object(
+            namespace['namespace'], up_object_name)
+        # List namespace objects and validate deletion
+        namespace_objects = [
+            namespace_object['name'] for namespace_object in
+            self.namespace_objects_client.list_namespace_objects(
+                namespace['namespace'])['objects']]
+        self.assertNotIn(up_object_name, namespace_objects)
+
+    @test.idempotent_id('a2a3615e-3b5c-3f6a-a2b1-1ba3574ae738')
+    def test_list_meta_namespace_objects(self):
+        # Create a namespace object
+        namespace = self.create_namespace()
+        meta_namespace_object = self._create_namespace_object(namespace)
+        # List namespace objects
+        namespace_objects = [
+            namespace_object['name'] for namespace_object in
+            self.namespace_objects_client.list_namespace_objects(
+                namespace['namespace'])['objects']]
+        self.assertIn(meta_namespace_object['name'], namespace_objects)
+
+    @test.idempotent_id('b1a3674e-3b4c-3f6a-a3b4-1ba3573ca768')
+    def test_show_meta_namespace_objects(self):
+        # Create a namespace object
+        namespace = self.create_namespace()
+        namespace_object = self._create_namespace_object(namespace)
+        # Show a namespace object
+        body = self.namespace_objects_client.show_namespace_object(
+            namespace['namespace'], namespace_object['name'])
+        self.assertEqual(namespace_object['name'], body['name'])
diff --git a/tempest/clients.py b/tempest/clients.py
index e3466e5..f99060a 100644
--- a/tempest/clients.py
+++ b/tempest/clients.py
@@ -40,12 +40,11 @@
     }
     default_params_with_timeout_values.update(default_params)
 
-    def __init__(self, credentials, service=None, scope='project'):
+    def __init__(self, credentials, scope='project'):
         """Initialization of Manager class.
 
         Setup all services clients and make them available for tests cases.
         :param credentials: type Credentials or TestResources
-        :param service: Service name
         :param scope: default scope for tokens produced by the auth provider
         """
         _, identity_uri = get_auth_provider_class(credentials)
@@ -128,6 +127,8 @@
             self.image_member_client_v2 = self.image_v2.ImageMembersClient()
             self.namespaces_client = self.image_v2.NamespacesClient()
             self.resource_types_client = self.image_v2.ResourceTypesClient()
+            self.namespace_objects_client = \
+                self.image_v2.NamespaceObjectsClient()
             self.schemas_client = self.image_v2.SchemasClient()
             self.namespace_properties_client = \
                 self.image_v2.NamespacePropertiesClient()
diff --git a/tempest/common/credentials_factory.py b/tempest/common/credentials_factory.py
index bf8d30e..e6b46ed 100644
--- a/tempest/common/credentials_factory.py
+++ b/tempest/common/credentials_factory.py
@@ -233,7 +233,6 @@
 class AdminManager(clients.Manager):
     """Manager that uses admin credentials for its managed client objects"""
 
-    def __init__(self, service=None):
+    def __init__(self):
         super(AdminManager, self).__init__(
-            credentials=get_configured_admin_credentials(),
-            service=service)
+            credentials=get_configured_admin_credentials())
diff --git a/tempest/lib/services/image/v2/__init__.py b/tempest/lib/services/image/v2/__init__.py
index d359d4b..a35ce17 100644
--- a/tempest/lib/services/image/v2/__init__.py
+++ b/tempest/lib/services/image/v2/__init__.py
@@ -15,6 +15,8 @@
 from tempest.lib.services.image.v2.image_members_client import \
     ImageMembersClient
 from tempest.lib.services.image.v2.images_client import ImagesClient
+from tempest.lib.services.image.v2.namespace_objects_client import \
+    NamespaceObjectsClient
 from tempest.lib.services.image.v2.namespace_properties_client import \
     NamespacePropertiesClient
 from tempest.lib.services.image.v2.namespaces_client import NamespacesClient
@@ -22,5 +24,6 @@
     ResourceTypesClient
 from tempest.lib.services.image.v2.schemas_client import SchemasClient
 
-__all__ = ['ImageMembersClient', 'ImagesClient', 'NamespacePropertiesClient',
-           'NamespacesClient', 'ResourceTypesClient', 'SchemasClient']
+__all__ = ['ImageMembersClient', 'ImagesClient', 'NamespaceObjectsClient',
+           'NamespacePropertiesClient', 'NamespacesClient',
+           'ResourceTypesClient', 'SchemasClient']
diff --git a/tempest/lib/services/image/v2/namespace_objects_client.py b/tempest/lib/services/image/v2/namespace_objects_client.py
new file mode 100644
index 0000000..ac2e63e
--- /dev/null
+++ b/tempest/lib/services/image/v2/namespace_objects_client.py
@@ -0,0 +1,91 @@
+# Copyright 2016 EasyStack.
+# 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 oslo_serialization import jsonutils as json
+from six.moves.urllib import parse as urllib
+
+from tempest.lib.common import rest_client
+
+
+class NamespaceObjectsClient(rest_client.RestClient):
+    api_version = "v2"
+
+    def list_namespace_objects(self, namespace, **kwargs):
+        """Lists all namespace objects.
+
+        For a full list of available parameters, please refer to the official
+        API reference:
+        http://developer.openstack.org/api-ref/image/v2/metadefs-index.html#list-objects
+        """
+        url = 'metadefs/namespaces/%s/objects' % namespace
+        if kwargs:
+            url += '?%s' % urllib.urlencode(kwargs)
+        resp, body = self.get(url)
+        self.expected_success(200, resp.status)
+        body = json.loads(body)
+        return rest_client.ResponseBody(resp, body)
+
+    def create_namespace_object(self, namespace, **kwargs):
+        """Create a namespace object
+
+        For a full list of available parameters, please refer to the official
+        API reference:
+        http://developer.openstack.org/api-ref/image/v2/metadefs-index.html#create-object
+        """
+        url = 'metadefs/namespaces/%s/objects' % namespace
+        data = json.dumps(kwargs)
+        resp, body = self.post(url, data)
+        self.expected_success(201, resp.status)
+        body = json.loads(body)
+        return rest_client.ResponseBody(resp, body)
+
+    def update_namespace_object(self, namespace, object_name, **kwargs):
+        """Update a namespace object
+
+        For a full list of available parameters, please refer to the official
+        API reference:
+        http://developer.openstack.org/api-ref/image/v2/metadefs-index.html#update-object
+        """
+        url = 'metadefs/namespaces/%s/objects/%s' % (namespace, object_name)
+        data = json.dumps(kwargs)
+        resp, body = self.put(url, data)
+        self.expected_success(200, resp.status)
+        body = json.loads(body)
+        return rest_client.ResponseBody(resp, body)
+
+    def show_namespace_object(self, namespace, object_name):
+        """Show a namespace object
+
+        For a full list of available parameters, please refer to the official
+        API reference:
+        http://developer.openstack.org/api-ref/image/v2/metadefs-index.html#show-object
+        """
+        url = 'metadefs/namespaces/%s/objects/%s' % (namespace, object_name)
+        resp, body = self.get(url)
+        self.expected_success(200, resp.status)
+        body = json.loads(body)
+        return rest_client.ResponseBody(resp, body)
+
+    def delete_namespace_object(self, namespace, object_name):
+        """Delete a namespace object
+
+        For a full list of available parameters, please refer to the official
+        API reference:
+        http://developer.openstack.org/api-ref/image/v2/metadefs-index.html#delete-object
+        """
+        url = 'metadefs/namespaces/%s/objects/%s' % (namespace, object_name)
+        resp, _ = self.delete(url)
+        self.expected_success(204, resp.status)
+        return rest_client.ResponseBody(resp)
diff --git a/tempest/test.py b/tempest/test.py
index 17dc94c..039afa1 100644
--- a/tempest/test.py
+++ b/tempest/test.py
@@ -219,7 +219,6 @@
     """
 
     setUpClassCalled = False
-    _service = None
 
     # NOTE(andreaf) credentials holds a list of the credentials to be allocated
     # at class setup time. Credential types can be 'primary', 'alt', 'admin' or
@@ -533,8 +532,7 @@
             else:
                 raise lib_exc.InvalidCredentials(
                     "Invalid credentials type %s" % credential_type)
-        manager = cls.client_manager(credentials=creds.credentials,
-                                     service=cls._service)
+        manager = cls.client_manager(credentials=creds.credentials)
         # NOTE(andreaf) Ensure credentials have user and project id fields.
         # It may not be the case when using pre-provisioned credentials.
         manager.auth_provider.set_auth()
diff --git a/tempest/tests/lib/services/image/v2/test_namespace_object_client.py b/tempest/tests/lib/services/image/v2/test_namespace_object_client.py
new file mode 100644
index 0000000..8d29660
--- /dev/null
+++ b/tempest/tests/lib/services/image/v2/test_namespace_object_client.py
@@ -0,0 +1,210 @@
+# Copyright 2016 EasyStack. 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 tempest.lib.services.image.v2 import namespace_objects_client
+from tempest.tests.lib import fake_auth_provider
+from tempest.tests.lib.services import base
+
+
+class TestNamespaceObjectClient(base.BaseServiceTest):
+    FAKE_CREATE_SHOW_OBJECTS = {
+        "created_at": "2016-09-19T18:20:56Z",
+        "description": "You can configure the CPU limits.",
+        "name": "CPU Limits",
+        "properties": {
+            "quota:cpu_period": {
+                "description": "Specifies the enforcement interval",
+                "maximum": 1000000,
+                "minimum": 1000,
+                "title": "Quota: CPU Period",
+                "type": "integer"
+            },
+            "quota:cpu_quota": {
+                "description": "Specifies the maximum allowed bandwidth ",
+                "title": "Quota: CPU Quota",
+                "type": "integer"
+            },
+            "quota:cpu_shares": {
+                "description": "Specifies the proportional weighted share.",
+                "title": "Quota: CPU Shares",
+                "type": "integer"
+            }
+        },
+        "required": [],
+        "schema": "/v2/schemas/metadefs/object",
+        "self": "/v2/metadefs/namespaces/OS::Compute::Quota/objects/CPU",
+        "updated_at": "2016-09-19T18:20:56Z"
+    }
+
+    FAKE_LIST_OBJECTS = {
+        "objects": [
+            {
+                "created_at": "2016-09-18T18:16:35Z",
+                "description": "You can configure the CPU limits.",
+                "name": "CPU Limits",
+                "properties": {
+                    "quota:cpu_period": {
+                        "description": "Specifies the enforcement interval ",
+                        "maximum": 1000000,
+                        "minimum": 1000,
+                        "title": "Quota: CPU Period",
+                        "type": "integer"
+                    },
+                    "quota:cpu_quota": {
+                        "description": "Specifies the maximum.",
+                        "title": "Quota: CPU Quota",
+                        "type": "integer"
+                    },
+                    "quota:cpu_shares": {
+                        "description": " Desc.",
+                        "title": "Quota: CPU Shares",
+                        "type": "integer"
+                    }
+                },
+                "required": [],
+                "schema": "/v2/schemas/metadefs/object",
+                "self":
+                    "/v2/metadefs/namespaces/OS::Compute::Quota/objects/CPU"
+            },
+            {
+                "created_at": "2016-09-18T18:16:35Z",
+                "description": "Using disk I/O quotas.",
+                "name": "Disk QoS",
+                "properties": {
+                    "quota:disk_read_bytes_sec": {
+                        "description": "Sets disk I/O quota.",
+                        "title": "Quota: Disk read bytes / sec",
+                        "type": "integer"
+                    },
+                    "quota:disk_read_iops_sec": {
+                        "description": "Sets disk I/O quota",
+                        "title": "Quota: Disk read IOPS / sec",
+                        "type": "integer"
+                    },
+                    "quota:disk_total_bytes_sec": {
+                        "description": "Sets disk I/O quota.",
+                        "title": "Quota: Disk Total Bytes / sec",
+                        "type": "integer"
+                    },
+                    "quota:disk_total_iops_sec": {
+                        "description": "Sets disk I/O quota.",
+                        "title": "Quota: Disk Total IOPS / sec",
+                        "type": "integer"
+                    },
+                    "quota:disk_write_bytes_sec": {
+                        "description": "Sets disk I/O quota.",
+                        "title": "Quota: Disk Write Bytes / sec",
+                        "type": "integer"
+                    },
+                    "quota:disk_write_iops_sec": {
+                        "description": "Sets disk I/O quota.",
+                        "title": "Quota: Disk Write IOPS / sec",
+                        "type": "integer"
+                    }
+                },
+                "required": [],
+                "schema": "/v2/schemas/metadefs/object",
+                "self":
+                "/v2/metadefs/namespaces/OS::Compute::Quota/objects/Disk QoS"
+            },
+        ],
+        "schema": "v2/schemas/metadefs/objects"
+    }
+
+    FAKE_UPDATE_OBJECTS = {
+        "description": "You can configure the CPU limits.",
+        "name": "CPU",
+        "properties": {
+            "quota:cpu_shares": {
+                "description": "Specify.",
+                "title": "Quota: CPU Shares",
+                "type": "integer"
+            }
+        },
+        "required": []
+    }
+
+    def setUp(self):
+        super(TestNamespaceObjectClient, self).setUp()
+        fake_auth = fake_auth_provider.FakeAuthProvider()
+        self.client = namespace_objects_client.NamespaceObjectsClient(
+            fake_auth, 'image', 'regionOne')
+
+    def _test_create_namespace_objects(self, bytes_body=False):
+        self.check_service_client_function(
+            self.client.create_namespace_object,
+            'tempest.lib.common.rest_client.RestClient.post',
+            self.FAKE_CREATE_SHOW_OBJECTS,
+            bytes_body, status=201,
+            namespace="OS::Compute::Hypervisor",
+            object_name="OS::Glance::Image")
+
+    def _test_list_namespace_objects(self, bytes_body=False):
+        self.check_service_client_function(
+            self.client.list_namespace_objects,
+            'tempest.lib.common.rest_client.RestClient.get',
+            self.FAKE_LIST_OBJECTS,
+            bytes_body,
+            namespace="OS::Compute::Hypervisor")
+
+    def _test_show_namespace_objects(self, bytes_body=False):
+        self.check_service_client_function(
+            self.client.show_namespace_object,
+            'tempest.lib.common.rest_client.RestClient.get',
+            self.FAKE_CREATE_SHOW_OBJECTS,
+            bytes_body,
+            namespace="OS::Compute::Hypervisor",
+            object_name="OS::Glance::Image")
+
+    def _test_update_namespace_objects(self, bytes_body=False):
+        self.check_service_client_function(
+            self.client.update_namespace_object,
+            'tempest.lib.common.rest_client.RestClient.put',
+            self.FAKE_UPDATE_OBJECTS,
+            bytes_body,
+            namespace="OS::Compute::Hypervisor",
+            object_name="OS::Glance::Image",
+            name="CPU")
+
+    def test_create_namespace_object_with_str_body(self):
+        self._test_create_namespace_objects()
+
+    def test_create_namespace_object_with_bytes_body(self):
+        self._test_create_namespace_objects(bytes_body=True)
+
+    def test_list_namespace_object_with_str_body(self):
+        self._test_list_namespace_objects()
+
+    def test_list_namespace_object_with_bytes_body(self):
+        self._test_list_namespace_objects(bytes_body=True)
+
+    def test_show_namespace_object_with_str_body(self):
+        self._test_show_namespace_objects()
+
+    def test_show_namespace_object_with_bytes_body(self):
+        self._test_show_namespace_objects(bytes_body=True)
+
+    def test_update_namespace_object_with_str_body(self):
+        self._test_update_namespace_objects()
+
+    def test_update_namespace_object_with_bytes_body(self):
+        self._test_update_namespace_objects(bytes_body=True)
+
+    def test_delete_namespace_objects(self):
+        self.check_service_client_function(
+            self.client.delete_namespace_object,
+            'tempest.lib.common.rest_client.RestClient.delete',
+            {}, namespace="OS::Compute::Hypervisor",
+            object_name="OS::Glance::Image",
+            status=204)