diff --git a/config_tempest/main.py b/config_tempest/main.py
index 0bb9ece8..80acdf93 100755
--- a/config_tempest/main.py
+++ b/config_tempest/main.py
@@ -184,7 +184,7 @@ def set_options(conf, deployer_input, non_admin, image_path, overrides=[],
         conf.set("auth", "admin_username", "")
         conf.set("auth", "admin_project_name", "")
         conf.set("auth", "admin_password", "")
-        conf.set("auth", "use_dynamic_credentials", "False")
+        conf.set("auth", "use_dynamic_credentials", "False", priority=True)
 
     # get and set auth data from client's config
     if cloud_creds:
@@ -192,7 +192,7 @@ def set_options(conf, deployer_input, non_admin, image_path, overrides=[],
 
     if accounts_path:
         # new way for running using accounts file
-        conf.set("auth", "use_dynamic_credentials", "False")
+        conf.set("auth", "use_dynamic_credentials", "False", priority=True)
         conf.set("auth", "test_accounts_file",
                  os.path.abspath(accounts_path))
 
diff --git a/config_tempest/tests/base.py b/config_tempest/tests/base.py
index cfbfd649..6e3da0e3 100644
--- a/config_tempest/tests/base.py
+++ b/config_tempest/tests/base.py
@@ -62,7 +62,7 @@ class BaseConfigTempestTest(base.BaseTestCase):
         conf.set("auth", "admin_username", "admin")
         conf.set("auth", "admin_project_name", "adminProject")
         conf.set("auth", "admin_password", "adminPass")
-        conf.set("auth", "use_dynamic_credentials", "False")
+        conf.set("auth", "use_dynamic_credentials", "False", priority=True)
         return conf
 
     def _get_alt_conf(self, V2, V3):
@@ -79,7 +79,7 @@ class BaseConfigTempestTest(base.BaseTestCase):
         conf.set("auth", "admin_username", "admin")
         conf.set("auth", "admin_project_name", "adminProject")
         conf.set("auth", "admin_password", "adminPass")
-        conf.set("auth", "use_dynamic_credentials", "True")
+        conf.set("auth", "use_dynamic_credentials", "True", priority=True)
         return conf
 
     def _get_creds(self, conf, admin=False, v2=False):
diff --git a/config_tempest/tests/test_tempest_conf.py b/config_tempest/tests/test_tempest_conf.py
index 9fc5726c..cd76218b 100644
--- a/config_tempest/tests/test_tempest_conf.py
+++ b/config_tempest/tests/test_tempest_conf.py
@@ -36,23 +36,28 @@ class TestTempestConf(BaseConfigTempestTest):
         # set value wihout priority (default: priority=False)
         resp = self.conf.set("section", "key", "value")
         # value should be overwritten, because it wasn't set with priority
-        resp = self.conf.set("section", "key", "value")
+        resp = self.conf.set("section", "key", "new_value")
         self.assertTrue(resp)
+        self.assertEqual(self.conf.get("section", "key"), "new_value")
 
     def test_set_value_overwrite_priority(self):
         resp = self.conf.set("sectionPriority", "key", "value", priority=True)
-        resp = self.conf.set("sectionPriority", "key", "value")
+        resp = self.conf.set("sectionPriority", "key", "new_value")
         self.assertFalse(resp)
+        self.assertEqual(self.conf.get("sectionPriority", "key"), "value")
 
     def test_set_value_overwrite_by_priority(self):
         resp = self.conf.set("section", "key", "value")
-        resp = self.conf.set("section", "key", "value", priority=True)
+        resp = self.conf.set("section", "key", "new_value", priority=True)
         self.assertTrue(resp)
+        self.assertEqual(self.conf.get("section", "key"), "new_value")
 
     def test_set_value_overwrite_priority_by_priority(self):
         resp = self.conf.set("sectionPriority", "key", "value", priority=True)
-        resp = self.conf.set("sectionPriority", "key", "value", priority=True)
+        resp = self.conf.set("sectionPriority", "key",
+                             "new_value", priority=True)
         self.assertTrue(resp)
+        self.assertEqual(self.conf.get("sectionPriority", "key"), "new_value")
 
     def test_get_bool_value(self):
         self.assertTrue(self.conf.get_bool_value("True"))