bpo-19756: Change remote NNTP server to localhost server for most tests by berkerpeksag · Pull Request #9461

bpo-19756: Change remote NNTP server to localhost server for most tests by berkerpeksag · Pull Request #9461 · python/cpython

* Local server is based on the existing NNTPv2Handler class
* Reintegrate test_starttls() into NetworkedNNTPTestsMixin
* Only test_with_statement() talks to the remote NNTP_HOST now
* Make tests in NetworkedNNTPTestsMixin stricter, because the server
  responses are predetermined now
* Add mock comp.lang.python support to NNTPv1Handler.handle_GROUP()
* Add support for rejecting passwords in NNTPv1Handler.handle_AUTHINFO()
* New message number with non-UTF-8 message body for ARTICLE, HEAD, BODY, and
  non-UTF-8 subject for OVER, XOVER

Initial patch by Martin Panter.