anchor.diff:      State.
   
   
  --spec persist_nodes([node_info()]) -> ok | error.
  +-spec persist_nodes(nodes_map()) -> ok | error.
   persist_nodes(Ns) ->
       persist_nodes(Ns, ?PERSIST_FILE).
   
   
  --spec persist_nodes([node_info()], binary()) -> ok | error.
  +-spec persist_nodes(nodes_map(), binary()) -> ok | error.
   persist_nodes(Ns, File) ->
       % as of now we convert the nodes into a JSON representation
       % no specific reason for this - maybe because we might
  
positive.code:             end;
          {error, enoent} ->
              % file does not exist -> this is totally alright
              [];
          Error ->
              lager:warning("error on loading nodes file: ~p", [Error]),
              []
      end.
  
  
  
negative.code:                              load_nodes()
                       end,
  
      [?_assertEqual(maps:new(), load_nodes(<<"/tmp/probably/does/not/exist.json">>)),
       ?_assertEqual(Nodes, PersistAndLoad(Nodes))
      ].
  
  