anchor.diff:       ?_assertEqual(unchanged, ?state:interesting(7, S2)),
        ?_assertEqual(unchanged, ?state:interesting(6, S2))].
   
  +interesting_sent_test_() ->
  +    L0 = ?state:interested(true, ?state:hasnone(?state:new(testsize()))),
  +    L1 = ?state:hasone(0, L0),
  +    L2 = ?state:hasone(1, L1),
  +    L3 = ?state:interested(false, L1),
  +
  +    R0 = ?state:hasnone(?state:new(testsize())),
  +    R1 = ?state:hasone(0, R0),
  +    R2 = ?state:hasone(1, R1),
  +
  +    [?_assertEqual(unchanged, ?state:interesting(0, R0, L1)),
  +     ?_assertEqual(false,     ?state:interesting(0, R1, L1)),
  +     ?_assertEqual(unchanged, ?state:interesting(0, R2, L1)),
  +     ?_assertEqual(false,     ?state:interesting(0, R2, L2)),
  +     ?_assertEqual(unchanged, ?state:interesting(0, R1, L3))].
  +
   -endif.
   
  
positive.code:      ?_assertError(badarg, ?state:interested(true, S1)),
       ?_assert(?state:interested(S1))].
  
  interesting_not_test_() ->
      S0 = ?state:new(testsize()),
      S1 = ?state:hasone(7, S0),
      S2 = ?state:interested(true, S1),
  
negative.code:     State = ?state:new(testsize()),
      [?_assert(?state:choked(State)),
       ?_assertNot(?state:interested(State)),
       ?_assertNot(?state:seeder(State)),
       ?_assertError(badarg, ?state:pieces(State)),
       ?_assertError(badarg, ?state:interesting(0, State))].
  
  