anchor.diff:      %% test multiple v6-to-v6 change
       [CSP_TCP6, CSP_TCP6, CSP_TCP6] = change_sipdst_protocol(tcp, [CSP_UDP6, CSP_TCP6, CSP_TLS6]),
   
  +    io:format("test: change_sipdst_protocol/2 - 6~n"),
  +    %% test error tuple
  +    {error, undefined} = change_sipdst_protocol(tcp, {error, undefined}),
  +
       ok.
  
positive.code: %%--------------------------------------------------------------------
  %% Function: change_sipdst_protocol(Proto, DstList)
  %%           Proto   = atom(), tcp | udp | tls
  %%           DstList = list() of Entry
  %%             Entry = sipdst record() | {error, Reason} tuple()
  %% Descrip.: Go through a list of Entry. For each Entry that is a
  %%           sipdst record, change the records 'proto' element into
  %%           Proto or, if the old protocol was a v6-protocol, into
  %%           the v6 variant of Proto.
  %% Returns : list() of Entry
  %%--------------------------------------------------------------------
  change_sipdst_protocol(Proto, In) when is_atom(Proto), is_list(In) ->
      Proto6 = case Proto of
  		 tcp -> tcp6;
  
negative.code:   when is_record(H, sipdst), OldProto == tcp6; OldProto == udp6; OldProto == tls6 ->
      This = H#sipdst{proto=Proto6},
      change_sipdst_protocol2(Proto, Proto6, T, [This | Res]);
  %%
  %% No more entrys
  %%
  