def test_plainAuthenticationEmptyPassword(self):
        """
        Test that giving an empty password for plain auth succeeds.
        """
        loginArgs = []
        self.server.portal = self.portalFactory(loginArgs)

        self.server.dataReceived(b'EHLO\r\n')
        self.transport.clear()

        self.assertServerResponse(
            b'AUTH LOGIN\r\n',
            [b"334 " + base64.b64encode(b"User Name\0").strip()])

        self.assertServerResponse(
            base64.b64encode(b'username') + b'\r\n',
            [b"334 " + base64.b64encode(b"Password\0").strip()])

        self.assertServerResponse(b'\r\n', [])
        self.assertServerAuthenticated(loginArgs, password=b'')

        Test that giving an empty password for plain auth succeeds.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_smtp.py