anchor.diff:  
   %% Assume the resource doesn't exist if it's not a regular file.
   
  --spec resource_exists(Req, State)
  -		     -> {boolean(), Req, State}
  -			    when State::state().
  +-spec resource_exists(Req, State) -> {boolean(), Req, State} when State::state().
   resource_exists(Req, State={_, {ok, #file_info{type=regular}}, _}) ->
       {true, Req, State};
   resource_exists(Req, State) ->
  
positive.code: fullpath([Segment|Tail], Acc) ->
      fullpath(Tail, [Segment|Acc]).
  
  rest_init_info(Req, Path, Extra) ->
      Info = file:read_file_info(Path, [{time, universal}]),
      {ok, Req, {Path, Info, Extra}}.
  
  -ifdef(TEST).
  fullpath_test_() ->
  
negative.code: -spec generate_etag(Req, State)
  		   -> {{strong | weak, binary()}, Req, State}
  			  when State::state().
  generate_etag(Req, State={Path, {ok, #file_info{size=Size, mtime=Mtime}}, Extra}) ->
      case lists:keyfind(etag, 1, Extra) of
  	false ->
  	    {generate_default_etag(Size, Mtime), Req, State};
  