Exception happened during processing of request from ('127.0.0.1', 55017)
Traceback (most recent call last):
  File "/home/heimes/dev/python/py3k/Lib/SocketServer.py", line 222, in
handle_request
    self.process_request(request, client_address)
  File "/home/heimes/dev/python/py3k/Lib/SocketServer.py", line 241, in
process_request
    self.finish_request(request, client_address)
  File "/home/heimes/dev/python/py3k/Lib/SocketServer.py", line 254, in
finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/home/heimes/dev/python/py3k/Lib/SocketServer.py", line 522, in
__init__
    self.handle()
  File "/home/heimes/dev/python/py3k/Lib/BaseHTTPServer.py", line 330,
in handle
    self.handle_one_request()
  File "/home/heimes/dev/python/py3k/Lib/BaseHTTPServer.py", line 324,
in handle_one_request
    method()
  File "/home/heimes/dev/python/py3k/Lib/SimpleXMLRPCServer.py", line
430, in do_POST
    self.report_404()
  File "/home/heimes/dev/python/py3k/Lib/SimpleXMLRPCServer.py", line
486, in report_404
    self.wfile.write(response)
  File "/home/heimes/dev/python/py3k/Lib/socket.py", line 220, in write
    return self._sock.send(b)
TypeError: send() argument 1 must be bytes or read-only buffer, not str
----------------------------------------

After I altered the response to bytes:

  File "/home/heimes/dev/python/py3k/Lib/SimpleXMLRPCServer.py", line
430, in do_POST
    self.report_404()
  File "/home/heimes/dev/python/py3k/Lib/SimpleXMLRPCServer.py", line
489, in report_404
    self.connection.shutdown(0)
socket.error: [Errno 107] Transport endpoint is not connected
----------------------------------------

I disabled test_404 in test_xmlrpc.py r59423

Is disabling a test the right solution?

No, I've fixed the three failing or blocking tests in r59429 and r59434.