anchor.diff:  
   content_types_provided(Req, State) ->
       {[{"application/json", to_json}], Req, State}.
  +
  +delete_resource(Req, State = #state{mode = document}) ->
  +    ok = m_rsc:delete(State#state.document_id, State#state.context),
  +    {true, Req, State}.
   
   to_json(Req, State = #state{mode = collection}) ->
       Context = State#state.context,
  
positive.code:               {Methods, _, _} = allowed_methods(req, state),
                ?assert(lists:member('GET', Methods)),
                ?assert(lists:member('POST', Methods)),
                ?assert(lists:member('HEAD', Methods)),
                ?assertEqual(3, erlang:length(Methods)),
                ok
        end
      ].
  
negative.code:         , malformed_request/2
          , allowed_methods/2
          , resource_exists/2
          , delete_resource/2
          , content_types_provided/2
          , to_json/2
          , process_post/2
  