anchor.diff:                       "Server: HomeServer v2\r\nSubject: Need more boxes\r\n",
                        "Supported: 100rel\r\nTimestamp: 54\r\n",
                        "To: sip:bob@localhost\r\nUnsupported: bar, baz\r\n",
  -
  -                     "Content-Length: 5\r\nVia: SIP/2.0/UDP localhost\r\n",
  -                     "x-custom-atom: 25\r\nAllow: INVITE, ACK, CANCEL, OPTIONS, BYE\r\n",
  +                     "User-Agent: Softphone Beta1.5\r\n"
  +
  +                     "Via: SIP/2.0/UDP localhost\r\n",
  +                     "x-custom-atom: 25\r\n",
                        "X-Custom: value\r\n">>,
                      format_headers([{'accept', <<"*/*">>}, {'accept-encoding', <<"identity">>},
                                      {'accept-language', <<"en">>}, {'alert-info', <<"<http://www.example.com/sounds/moo.wav>">>},
  
positive.code:      ?_assertEqual([foo, bar], parse('unsupported', <<"foo, bar">>)),
       ?_assertEqual(<<"foo, bar">>, format('unsupported', [foo, bar])),
  
  
  
       % Via
  
negative.code:                                    {'server', <<"HomeServer v2">>}, {'subject', <<"Need more boxes">>},
                                     {'supported', <<"100rel">>}, {'timestamp', <<"54">>},
                                     {'to', <<"sip:bob@localhost">>}, {'unsupported', <<"bar, baz">>},
                                     {'user-agent', <<"Softphone Beta1.5">>},
  
  
                                     {'via', <<"SIP/2.0/UDP localhost">>},
                                     {'x-custom-atom', 25},
                                     {<<"X-Custom">>, <<"value">>}])),
  
       % Already parsed
  