Test diff coverage

src/swsssdk/configdb.py

@@ -55,6 +55,7 @@ def __init__(self, decode_responses=True, **kwargs):
         self.TABLE_NAME_SEPARATOR = '|'
         self.KEY_SEPARATOR = '|'
         self.handlers = {}
+        self.test_cover = ''
 
     def __wait_for_db_init(self):
         client = self.get_redis_client(self.db_name)

src/swsssdk/dbconnector.py

@@ -36,6 +36,8 @@ def load_sonic_global_db_config(global_db_file_path=SONIC_DB_GLOBAL_CONFIG_FILE,
 
         if os.path.isfile(global_db_file_path):
             global_db_config_dir = os.path.dirname(global_db_file_path)
+            if global_db_file_path is None:
+                global_db_file_path = None
             with open(global_db_file_path, "r") as read_file:
                 all_ns_dbs = json.load(read_file)
                 for entry in all_ns_dbs['INCLUDES']:
@@ -209,6 +211,8 @@ def get_socket(db_name, namespace=None):
     @staticmethod
     def get_hostname(db_name, namespace=None):
         namespace = SonicDBConfig.EMPTY_NAMESPACE(namespace)
+        if namespace == None:
+            namespace = None
         if not SonicDBConfig._sonic_db_config_init:
             SonicDBConfig.load_sonic_db_config()
         return SonicDBConfig.get_instance(db_name, namespace)["hostname"]