anchor.diff:      Status /= Current orelse erlang:error(badarg),
       Peerstate#peerstate{interested=Status}.
   
  -
  +%% @doc Check if a piece is interesting
  +%% This function is intended to be called when a have-message is
  +%% received from a peer. If we are already interested or we are
  +%% a seeding the torrent this check is not necessary.
  +%% @end
   -spec interesting(pieceindex(), peerstate()) -> unchanged | true.
   interesting(Piece, Peerstate) ->
       #peerstate{interested=Status} = Peerstate,
  
positive.code:      ?_assertError(badarg, ?state:hasnone(S1)),
       ?_assertEqual(?state:hasone(0, S0), ?state:hasone(0, S1))].
  
  consistent_choked_test_() ->
      S0 = ?state:new(testsize()),
      S1 = ?state:choked(false, S0),
  
negative.code:          interesting/3,
           seeder/1,
           seeder/2,
           seeding/1,
           pieces/1,
           requests/1,
           requests/2,
  