diff --git a/Lib/test/test_nntplib.py b/Lib/test/test_nntplib.py
index 8d29681..1df64fa 100644
--- a/Lib/test/test_nntplib.py
+++ b/Lib/test/test_nntplib.py
@@ -5,6 +5,7 @@
 import unittest
 import functools
 import contextlib
+import nntplib
 import os.path
 import re
 import threading
@@ -12,7 +13,6 @@
 from test import support
 from test.support import socket_helper
 from nntplib import NNTP, GroupInfo
-import nntplib
 from unittest.mock import patch
 try:
     import ssl
@@ -411,6 +411,18 @@
     return (sio, file)
 
 
+class NNTPServer(nntplib.NNTP):
+
+    def __init__(self, f, host, readermode=None):
+        self.file = f
+        self.host = host
+        self._base_init(readermode)
+
+    def _close(self):
+        self.file.close()
+        del self.file
+
+
 class MockedNNTPTestsMixin:
     # Override in derived classes
     handler_class = None
@@ -426,7 +438,7 @@
     def make_server(self, *args, **kwargs):
         self.handler = self.handler_class()
         self.sio, file = make_mock_file(self.handler)
-        self.server = nntplib._NNTPBase(file, 'test.server', *args, **kwargs)
+        self.server = NNTPServer(file, 'test.server', *args, **kwargs)
         return self.server