TestFtpListingCmdsTLSMixin.test_nlst fails on Python 3.6

[felixonmars]

I am getting the following test failure when running with Python 3.6:

=================================== FAILURES ===================================
_____________________ TestFtpListingCmdsTLSMixin.test_nlst _____________________

self = <pyftpdlib.test.test_functional_ssl.TestFtpListingCmdsTLSMixin testMethod=test_nlst>

    @unittest.skipIf(TRAVIS or os.name == 'nt', "may fail on travis/windows")
    def test_nlst(self):
>       super(TestFtpListingCmdsTLSMixin, self).test_nlst()

pyftpdlib/test/test_functional_ssl.py:136:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
pyftpdlib/test/test_functional.py:1132: in test_nlst
    self._test_listing_cmds('nlst')
pyftpdlib/test/test_functional.py:1125: in _test_listing_cmds
    self.client.retrlines('%s %s' % (cmd, tempdir), x.append)
/usr/lib/python3.6/ftplib.py:485: in retrlines
    conn.unwrap()
/usr/lib/python3.6/ssl.py:1051: in unwrap
    s = self._sslobj.unwrap()
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <ssl.SSLObject object at 0x7f841ad96748>

    def unwrap(self):
        """Start the SSL shutdown handshake."""
>       return self._sslobj.shutdown()
E       OSError: [Errno 0] Error

/usr/lib/python3.6/ssl.py:698: OSError
============== 1 failed, 714 passed, 55 skipped in 28.58 seconds ===============

The versions:

platform linux -- Python 3.6.5, pytest-3.5.1, py-1.5.3, pluggy-0.6.0
rootdir: /build/python-pyftpdlib/src/pyftpdlib-1.5.4, inifile:

This error is not present on Python 2.7.

[sbraz]

Seems to be happening with Python 2.7 too https://bugs.gentoo.org/659786