anchor.diff:  %% Tests
   %% ----------------------------------------------------------------------
   groups() ->
  -    Tests = [checking, choked_reject, seed_transmission, leech_transmission,
  +    Tests = [choked_reject, seed_transmission, leech_transmission,
                seed_leech, partial_downloading, udp_seed_leech, bep9,
  -             down_udp_tracker, choked_seed_leech],
  +             down_udp_tracker, choked_seed_leech, checking],
   %   [{main_group, [shuffle], Tests}].
       [{main_group, [], Tests}].
   
  
positive.code: enable_dht(AppConfig) ->
      [{dht, true}|AppConfig].
  
  
negative.code: ensure_broken_file(Fn, BrokenFn) ->
      case filelib:is_regular(BrokenFn) of
  	true  -> ok;
  	false -> file:copy(Fn, BrokenFn), break_file(BrokenFn)
      end.
  
  
  break_file(BrokenFn) ->
      random:seed(now()),
      {ok, Fd} = file:open(BrokenFn, [write, read, binary]),
      {ok, TotalSize} = file:position(Fd, eof),
      %% Modify 10 chunks in the file.
      write_bad_chunks(Fd, TotalSize, 10),
  