diff --git a/tempest/api/identity/admin/v3/test_default_project_id.py b/tempest/api/identity/admin/v3/test_default_project_id.py
index 3616e77..59ffc19 100644
--- a/tempest/api/identity/admin/v3/test_default_project_id.py
+++ b/tempest/api/identity/admin/v3/test_default_project_id.py
@@ -69,7 +69,7 @@
         admin_role_id = admin_role['id']
 
         # grant the admin role to the user on his project
-        self.roles_client.assign_user_role_on_project(proj_id, user_id,
+        self.roles_client.create_user_role_on_project(proj_id, user_id,
                                                       admin_role_id)
 
         # create a new client with user's credentials (NOTE: unscoped token!)
diff --git a/tempest/api/identity/admin/v3/test_roles.py b/tempest/api/identity/admin/v3/test_roles.py
index 4ecf0a5..f5bf923 100644
--- a/tempest/api/identity/admin/v3/test_roles.py
+++ b/tempest/api/identity/admin/v3/test_roles.py
@@ -94,7 +94,7 @@
 
     @test.idempotent_id('c6b80012-fe4a-498b-9ce8-eb391c05169f')
     def test_grant_list_revoke_role_to_user_on_project(self):
-        self.roles_client.assign_user_role_on_project(self.project['id'],
+        self.roles_client.create_user_role_on_project(self.project['id'],
                                                       self.user_body['id'],
                                                       self.role['id'])
 
@@ -115,7 +115,7 @@
 
     @test.idempotent_id('6c9a2940-3625-43a3-ac02-5dcec62ef3bd')
     def test_grant_list_revoke_role_to_user_on_domain(self):
-        self.roles_client.assign_user_role_on_domain(
+        self.roles_client.create_user_role_on_domain(
             self.domain['id'], self.user_body['id'], self.role['id'])
 
         roles = self.roles_client.list_user_roles_on_domain(
@@ -136,7 +136,7 @@
     @test.idempotent_id('cbf11737-1904-4690-9613-97bcbb3df1c4')
     def test_grant_list_revoke_role_to_group_on_project(self):
         # Grant role to group on project
-        self.roles_client.assign_group_role_on_project(
+        self.roles_client.create_group_role_on_project(
             self.project['id'], self.group_body['id'], self.role['id'])
         # List group roles on project
         roles = self.roles_client.list_group_roles_on_project(
@@ -170,7 +170,7 @@
 
     @test.idempotent_id('4bf8a70b-e785-413a-ad53-9f91ce02faa7')
     def test_grant_list_revoke_role_to_group_on_domain(self):
-        self.roles_client.assign_group_role_on_domain(
+        self.roles_client.create_group_role_on_domain(
             self.domain['id'], self.group_body['id'], self.role['id'])
 
         roles = self.roles_client.list_group_roles_on_domain(
diff --git a/tempest/api/identity/admin/v3/test_tokens.py b/tempest/api/identity/admin/v3/test_tokens.py
index fcf4772..8706cf7 100644
--- a/tempest/api/identity/admin/v3/test_tokens.py
+++ b/tempest/api/identity/admin/v3/test_tokens.py
@@ -83,11 +83,11 @@
         self.addCleanup(self.roles_client.delete_role, role['id'])
 
         # Grant the user the role on both projects.
-        self.roles_client.assign_user_role_on_project(project1['id'],
+        self.roles_client.create_user_role_on_project(project1['id'],
                                                       user['id'],
                                                       role['id'])
 
-        self.roles_client.assign_user_role_on_project(project2['id'],
+        self.roles_client.create_user_role_on_project(project2['id'],
                                                       user['id'],
                                                       role['id'])
 
diff --git a/tempest/api/identity/admin/v3/test_trusts.py b/tempest/api/identity/admin/v3/test_trusts.py
index 58e2ab8..4e69de8 100644
--- a/tempest/api/identity/admin/v3/test_trusts.py
+++ b/tempest/api/identity/admin/v3/test_trusts.py
@@ -77,11 +77,11 @@
         self.not_delegated_role_id = role['id']
 
         # Assign roles to trustor
-        self.roles_client.assign_user_role_on_project(
+        self.roles_client.create_user_role_on_project(
             self.trustor_project_id,
             self.trustor_user_id,
             self.delegated_role_id)
-        self.roles_client.assign_user_role_on_project(
+        self.roles_client.create_user_role_on_project(
             self.trustor_project_id,
             self.trustor_user_id,
             self.not_delegated_role_id)
diff --git a/tempest/api/identity/admin/v3/test_users.py b/tempest/api/identity/admin/v3/test_users.py
index 1bcec62..fd2683e 100644
--- a/tempest/api/identity/admin/v3/test_users.py
+++ b/tempest/api/identity/admin/v3/test_users.py
@@ -130,7 +130,7 @@
             self.addCleanup(
                 self.projects_client.delete_project, project_body['id'])
             # Assigning roles to user on project
-            self.roles_client.assign_user_role_on_project(project['id'],
+            self.roles_client.create_user_role_on_project(project['id'],
                                                           user['id'],
                                                           role['id'])
             assigned_project_ids.append(project['id'])
diff --git a/tempest/common/cred_client.py b/tempest/common/cred_client.py
index 4e3c395..73330df 100644
--- a/tempest/common/cred_client.py
+++ b/tempest/common/cred_client.py
@@ -74,7 +74,9 @@
             msg = 'No "%s" role found' % role_name
             raise lib_exc.NotFound(msg)
         try:
-            self._assign_user_role(project, user, role)
+            self.roles_client.create_user_role_on_project(project['id'],
+                                                          user['id'],
+                                                          role['id'])
         except lib_exc.Conflict:
             LOG.debug("Role %s already assigned on project %s for user %s" % (
                 role['id'], project['id'], user['id']))
@@ -124,11 +126,6 @@
             tenant_name=project['name'], tenant_id=project['id'],
             password=password)
 
-    def _assign_user_role(self, project, user, role):
-        self.roles_client.create_user_role_on_project(project['id'],
-                                                      user['id'],
-                                                      role['id'])
-
 
 class V3CredsClient(CredsClient):
     project_id_param = 'project_id'
@@ -176,11 +173,6 @@
             domain_id=self.creds_domain['id'],
             domain_name=self.creds_domain['name'])
 
-    def _assign_user_role(self, project, user, role):
-        self.roles_client.assign_user_role_on_project(project['id'],
-                                                      user['id'],
-                                                      role['id'])
-
     def assign_user_role_on_domain(self, user, role_name, domain=None):
         """Assign the specified role on a domain
 
@@ -198,7 +190,7 @@
             msg = 'No "%s" role found' % role_name
             raise lib_exc.NotFound(msg)
         try:
-            self.roles_client.assign_user_role_on_domain(
+            self.roles_client.create_user_role_on_domain(
                 domain['id'], user['id'], role['id'])
         except lib_exc.Conflict:
             LOG.debug("Role %s already assigned on domain %s for user %s",
diff --git a/tempest/services/identity/v3/json/roles_client.py b/tempest/services/identity/v3/json/roles_client.py
index aab203f..3f165fa 100644
--- a/tempest/services/identity/v3/json/roles_client.py
+++ b/tempest/services/identity/v3/json/roles_client.py
@@ -13,6 +13,7 @@
 # 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
 
@@ -39,9 +40,13 @@
         body = json.loads(body)
         return rest_client.ResponseBody(resp, body)
 
-    def list_roles(self):
+    def list_roles(self, **params):
         """Get the list of Roles."""
-        resp, body = self.get("roles")
+
+        url = 'roles'
+        if params:
+            url += '?%s' % urllib.urlencode(params)
+        resp, body = self.get(url)
         self.expected_success(200, resp.status)
         body = json.loads(body)
         return rest_client.ResponseBody(resp, body)
@@ -64,14 +69,14 @@
         self.expected_success(204, resp.status)
         return rest_client.ResponseBody(resp, body)
 
-    def assign_user_role_on_project(self, project_id, user_id, role_id):
+    def create_user_role_on_project(self, project_id, user_id, role_id):
         """Add roles to a user on a project."""
         resp, body = self.put('projects/%s/users/%s/roles/%s' %
                               (project_id, user_id, role_id), None)
         self.expected_success(204, resp.status)
         return rest_client.ResponseBody(resp, body)
 
-    def assign_user_role_on_domain(self, domain_id, user_id, role_id):
+    def create_user_role_on_domain(self, domain_id, user_id, role_id):
         """Add roles to a user on a domain."""
         resp, body = self.put('domains/%s/users/%s/roles/%s' %
                               (domain_id, user_id, role_id), None)
@@ -124,22 +129,22 @@
         self.expected_success(204, resp.status)
         return rest_client.ResponseBody(resp)
 
-    def assign_group_role_on_project(self, project_id, group_id, role_id):
-        """Add roles to a user on a project."""
+    def create_group_role_on_project(self, project_id, group_id, role_id):
+        """Add roles to a group on a project."""
         resp, body = self.put('projects/%s/groups/%s/roles/%s' %
                               (project_id, group_id, role_id), None)
         self.expected_success(204, resp.status)
         return rest_client.ResponseBody(resp, body)
 
-    def assign_group_role_on_domain(self, domain_id, group_id, role_id):
-        """Add roles to a user on a domain."""
+    def create_group_role_on_domain(self, domain_id, group_id, role_id):
+        """Add roles to a group on a domain."""
         resp, body = self.put('domains/%s/groups/%s/roles/%s' %
                               (domain_id, group_id, role_id), None)
         self.expected_success(204, resp.status)
         return rest_client.ResponseBody(resp, body)
 
     def list_group_roles_on_project(self, project_id, group_id):
-        """list roles of a user on a project."""
+        """list roles of a group on a project."""
         resp, body = self.get('projects/%s/groups/%s/roles' %
                               (project_id, group_id))
         self.expected_success(200, resp.status)
@@ -147,7 +152,7 @@
         return rest_client.ResponseBody(resp, body)
 
     def list_group_roles_on_domain(self, domain_id, group_id):
-        """list roles of a user on a domain."""
+        """list roles of a group on a domain."""
         resp, body = self.get('domains/%s/groups/%s/roles' %
                               (domain_id, group_id))
         self.expected_success(200, resp.status)
@@ -155,14 +160,14 @@
         return rest_client.ResponseBody(resp, body)
 
     def delete_role_from_group_on_project(self, project_id, group_id, role_id):
-        """Delete role of a user on a project."""
+        """Delete role of a group on a project."""
         resp, body = self.delete('projects/%s/groups/%s/roles/%s' %
                                  (project_id, group_id, role_id))
         self.expected_success(204, resp.status)
         return rest_client.ResponseBody(resp, body)
 
     def delete_role_from_group_on_domain(self, domain_id, group_id, role_id):
-        """Delete role of a user on a domain."""
+        """Delete role of a group on a domain."""
         resp, body = self.delete('domains/%s/groups/%s/roles/%s' %
                                  (domain_id, group_id, role_id))
         self.expected_success(204, resp.status)
@@ -170,7 +175,7 @@
 
     def check_role_from_group_on_project_existence(self, project_id,
                                                    group_id, role_id):
-        """Check role of a user on a project."""
+        """Check role of a group on a project."""
         resp, body = self.head('projects/%s/groups/%s/roles/%s' %
                                (project_id, group_id, role_id))
         self.expected_success(204, resp.status)
@@ -178,7 +183,7 @@
 
     def check_role_from_group_on_domain_existence(self, domain_id,
                                                   group_id, role_id):
-        """Check role of a user on a domain."""
+        """Check role of a group on a domain."""
         resp, body = self.head('domains/%s/groups/%s/roles/%s' %
                                (domain_id, group_id, role_id))
         self.expected_success(204, resp.status)
diff --git a/tempest/tests/common/test_dynamic_creds.py b/tempest/tests/common/test_dynamic_creds.py
index e7b9a4c..cfa1df6 100644
--- a/tempest/tests/common/test_dynamic_creds.py
+++ b/tempest/tests/common/test_dynamic_creds.py
@@ -55,7 +55,6 @@
     users_client = v2_users_client
     token_client_class = token_client.TokenClient
     fake_response = fake_identity._fake_v2_response
-    assign_role_on_project = 'create_user_role_on_project'
     tenants_client_class = tenants_client.TenantsClient
     delete_tenant = 'delete_tenant'
 
@@ -125,7 +124,7 @@
     def _mock_assign_user_role(self):
         tenant_fix = self.useFixture(mockpatch.PatchObject(
             self.roles_client.RolesClient,
-            self.assign_role_on_project,
+            'create_user_role_on_project',
             return_value=(rest_client.ResponseBody
                           (200, {}))))
         return tenant_fix
@@ -198,11 +197,11 @@
         self._mock_tenant_create('1234', 'fake_admin_tenant')
 
         user_mock = mock.patch.object(self.roles_client.RolesClient,
-                                      self.assign_role_on_project)
+                                      'create_user_role_on_project')
         user_mock.start()
         self.addCleanup(user_mock.stop)
         with mock.patch.object(self.roles_client.RolesClient,
-                               self.assign_role_on_project) as user_mock:
+                               'create_user_role_on_project') as user_mock:
             admin_creds = creds.get_admin_creds()
         user_mock.assert_has_calls([
             mock.call('1234', '1234', '1234')])
@@ -221,11 +220,11 @@
         self._mock_tenant_create('1234', 'fake_role_tenant')
 
         user_mock = mock.patch.object(self.roles_client.RolesClient,
-                                      self.assign_role_on_project)
+                                      'create_user_role_on_project')
         user_mock.start()
         self.addCleanup(user_mock.stop)
         with mock.patch.object(self.roles_client.RolesClient,
-                               self.assign_role_on_project) as user_mock:
+                               'create_user_role_on_project') as user_mock:
             role_creds = creds.get_creds_by_roles(
                 roles=['role1', 'role2'])
         calls = user_mock.mock_calls
@@ -612,7 +611,6 @@
     users_client = v3_users_client
     token_client_class = token_client.V3TokenClient
     fake_response = fake_identity._fake_v3_response
-    assign_role_on_project = 'assign_user_role_on_project'
     tenants_client_class = tenants_client.ProjectsClient
     delete_tenant = 'delete_project'
 
@@ -624,7 +622,7 @@
             return_value=dict(domains=[dict(id='default',
                                             name='Default')])))
         self.patchobject(self.roles_client.RolesClient,
-                         'assign_user_role_on_domain')
+                         'create_user_role_on_domain')
 
     def _mock_list_ec2_credentials(self, user_id, tenant_id):
         pass