diff --git a/tempest/api/object_storage/test_account_quotas.py b/tempest/api/object_storage/test_account_quotas.py
index b14adc0..a3098a5 100644
--- a/tempest/api/object_storage/test_account_quotas.py
+++ b/tempest/api/object_storage/test_account_quotas.py
@@ -68,7 +68,7 @@
         # Retrieve a ResellerAdmin auth data and use it to set a quota
         # on the client's account
         cls.reselleradmin_auth_data = \
-            cls.os_reselleradmin.get_auth_provider().auth_data
+            cls.os_reselleradmin.auth_provider.auth_data
 
     def setUp(self):
         super(AccountQuotasTest, self).setUp()
diff --git a/tempest/api/object_storage/test_account_quotas_negative.py b/tempest/api/object_storage/test_account_quotas_negative.py
index 402cd90..7648ea1 100644
--- a/tempest/api/object_storage/test_account_quotas_negative.py
+++ b/tempest/api/object_storage/test_account_quotas_negative.py
@@ -68,7 +68,7 @@
         # Retrieve a ResellerAdmin auth data and use it to set a quota
         # on the client's account
         cls.reselleradmin_auth_data = \
-            cls.os_reselleradmin.get_auth_provider().auth_data
+            cls.os_reselleradmin.auth_provider.auth_data
 
     def setUp(self):
         super(AccountQuotasNegativeTest, self).setUp()
diff --git a/tempest/api/object_storage/test_account_services_negative.py b/tempest/api/object_storage/test_account_services_negative.py
index ea93aa3..71eaab5 100644
--- a/tempest/api/object_storage/test_account_services_negative.py
+++ b/tempest/api/object_storage/test_account_services_negative.py
@@ -31,7 +31,7 @@
         test_os = clients.Manager(self.data.test_user,
                                   self.data.test_password,
                                   self.data.test_tenant)
-        test_auth_provider = test_os.get_auth_provider()
+        test_auth_provider = test_os.auth_provider
         # Get auth for the test user
         test_auth_provider.auth_data
 
diff --git a/tempest/api/object_storage/test_container_acl.py b/tempest/api/object_storage/test_container_acl.py
index 085ef51..c865ee1 100644
--- a/tempest/api/object_storage/test_container_acl.py
+++ b/tempest/api/object_storage/test_container_acl.py
@@ -27,7 +27,7 @@
         test_os = clients.Manager(cls.data.test_user,
                                   cls.data.test_password,
                                   cls.data.test_tenant)
-        cls.test_auth_data = test_os.get_auth_provider().auth_data
+        cls.test_auth_data = test_os.auth_provider.auth_data
 
     @classmethod
     def tearDownClass(cls):
diff --git a/tempest/api/object_storage/test_container_acl_negative.py b/tempest/api/object_storage/test_container_acl_negative.py
index a5a0950..547bf87 100644
--- a/tempest/api/object_storage/test_container_acl_negative.py
+++ b/tempest/api/object_storage/test_container_acl_negative.py
@@ -29,7 +29,7 @@
         test_os = clients.Manager(cls.data.test_user,
                                   cls.data.test_password,
                                   cls.data.test_tenant)
-        cls.test_auth_data = test_os.get_auth_provider().auth_data
+        cls.test_auth_data = test_os.auth_provider.auth_data
 
     @classmethod
     def tearDownClass(cls):
diff --git a/tempest/exceptions/__init__.py b/tempest/exceptions/__init__.py
index 06dee71..485f532 100644
--- a/tempest/exceptions/__init__.py
+++ b/tempest/exceptions/__init__.py
@@ -20,6 +20,10 @@
     message = "Invalid Configuration"
 
 
+class InvalidCredentials(base.TempestException):
+    message = "Invalid Credentials"
+
+
 class InvalidHttpSuccessCode(base.RestClientException):
     message = "The success code is different than the expected one"
 
diff --git a/tempest/manager.py b/tempest/manager.py
index 708447e..63235db 100644
--- a/tempest/manager.py
+++ b/tempest/manager.py
@@ -75,13 +75,12 @@
             tenant_name=CONF.identity.tenant_name
         )
 
-    def get_auth_provider(self, credentials=None):
-        auth_params = dict(client_type=getattr(self, 'client_type', None),
-                           interface=getattr(self, 'interface', None))
+    def get_auth_provider(self, credentials):
+        if credentials is None:
+            raise exceptions.InvalidCredentials(
+                'Credentials must be specified')
         auth_provider_class = self.get_auth_provider_class(self.auth_version)
-        # If invalid / incomplete credentials are provided, use default ones
-        if credentials is None or \
-                not auth_provider_class.check_credentials(credentials):
-            credentials = self.credentials
-        auth_params['credentials'] = credentials
-        return auth_provider_class(**auth_params)
+        return auth_provider_class(
+            client_type=getattr(self, 'client_type', None),
+            interface=getattr(self, 'interface', None),
+            credentials=credentials)