diff --git a/Lib/test/test_ftplib.py b/Lib/test/test_ftplib.py
index 0467c3c782b61d..795527382b2abb 100644
--- a/Lib/test/test_ftplib.py
+++ b/Lib/test/test_ftplib.py
@@ -1242,15 +1242,18 @@ def test_cli_commands(self, mock_netrc, mock_ftp_cls):
     @mock.patch('netrc.netrc', side_effect=OSError)
     def test_cli_retrieve_file(self, mock_netrc, mock_ftp_cls):
         mock_ftp = mock_ftp_cls.return_value
-        with mock.patch('sys.argv', ['ftplib', 'example.com', 'testfile.txt']):
+        with mock.patch('sys.argv', ['ftplib', 'example.com', 'testfile.txt']), \
+             mock.patch('sys.stdout') as mock_stdout:
             ftplib.test()
-        mock_ftp.retrbinary.assert_called_once()
-        args, kwargs = mock_ftp.retrbinary.call_args
-        self.assertEqual(args[0], 'RETR testfile.txt')
+        mock_ftp.retrbinary.assert_called_once_with(
+            'RETR testfile.txt', mock_stdout.buffer.write, 1024
+        )
+        mock_stdout.buffer.flush.assert_called_once()
+        mock_stdout.flush.assert_called_once()
         mock_ftp.quit.assert_called_once()
 
     @mock.patch('ftplib.FTP')
-    @mock.patch('netrc.netrc', side_effect=OSError('file not found'))
+    @mock.patch('netrc.netrc', side_effect=OSError)
     def test_cli_custom_rcfile_error(self, mock_netrc, mock_ftp_cls):
         with mock.patch('sys.argv', ['ftplib', '-rnonexistent.netrc', 'example.com']), \
              support.captured_stderr() as stderr: