test_ssl is too verbose #94609

Feature or enhancement

• turn loud but ignored server tracebacks into silent exceptions passed straight to a main thread for assertRaises checks. An example of how it's currently (note "ok" in the last line):

  test_connect_ex (test.test_ssl.SimpleBackgroundTests.test_connect_ex) ...  server:  new connection from ('127.0.0.1', 51236)
   
  server:  bad connection attempt from ('127.0.0.1', 51236):
  Traceback (most recent call last):
     File "D:\a\cpython\cpython\Lib\test\test_ssl.py", line 2371, in wrap_conn
      self.sslconn = self.server.context.wrap_socket(
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     File "D:\a\cpython\cpython\Lib\ssl.py", line 455, in wrap_socket
      return self.sslsocket_class._create(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     File "D:\a\cpython\cpython\Lib\ssl.py", line 1013, in _create
      self.do_handshake()
      ^^^^^^^^^^^^^^^^^^^
     File "D:\a\cpython\cpython\Lib\ssl.py", line 1284, in do_handshake
      self._sslobj.do_handshake()
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^
   ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine
  ok
  

• stop printing a dialog between a client and a server; use the same assertion mechanism instead. An example:

  test_alpn_protocols (test.test_ssl.ThreadedTests.test_alpn_protocols) ...  server:  new connection from ('127.0.0.1', 51305)
   client:  sending b'FOO\n'...
   server: connection cipher is now ('TLS_AES_256_GCM_SHA384', 'TLSv1.3', 256)
   client:  read b'foo\n'
   client:  sending b'FOO\n'...
   client:  read b'foo\n'
   client:  sending b'FOO\n'...
   client:  read b'foo\n'
   client:  closing connection.
   server:  new connection from ('127.0.0.1', 51307)
   client:  sending b'FOO\n'...
   server: connection cipher is now ('TLS_AES_256_GCM_SHA384', 'TLSv1.3', 256)
   client:  read b'foo\n'
   client:  sending b'FOO\n'...
   client:  read b'foo\n'
   client:  sending b'FOO\n'...
   client:  read b'foo\n'
   client:  closing connection.
   server:  new connection from ('127.0.0.1', 51309)
   client:  sending b'FOO\n'...
   server: connection cipher is now ('TLS_AES_256_GCM_SHA384', 'TLSv1.3', 256)
   client:  read b'foo\n'
   client:  sending b'FOO\n'...
   client:  read b'foo\n'
   client:  sending b'FOO\n'...
   client:  read b'foo\n'
   client:  closing connection.
   server:  new connection from ('127.0.0.1', 51311)
   client:  sending b'FOO\n'...
   server: connection cipher is now ('TLS_AES_256_GCM_SHA384', 'TLSv1.3', 256)
   client:  read b'foo\n'
   client:  sending b'FOO\n'...
   client:  read b'foo\n'
   client:  sending b'FOO\n'...
   client:  read b'foo\n'
   client:  closing connection.
  ok
  

Pitch

While (almost) all tests keep silence, test_ssl reports every nit into a console making the log bloated (>1200 lines) to the degree of being unusable for failure tracking.

In addition, all these reports must be looked through manually. Assertions should be used instead.

Linked PRs

• gh-94609: Make test_ssl.ThreadedEchoServer exceptions appear in a main thread #92475