anchor.diff:  %%%----------------------------------------------------------------------
   
   %% Instrument file Path and produce all interleavings of (Mod, Fun, Args).
  --spec analyze(string(), atom(), atom(), [any()]) -> 'true'.
  +-spec analyze(string(), atom(), atom(), [any()]) -> ?RET_NORMAL |
  +						    ?RET_HEISENBUG |
  +						    ?RET_INSTR_ERROR.
   
   analyze(File, Mod, Fun, Args) ->
       case instr:instrument_and_load(File) of
  
positive.code: 		 {Val3, Set3} = set_pop(Set2),
  		 List2 = lists:sort([Val1, Val2, Val3]),
  		 ?assertEqual(List1, List2),
  		 ?assert(set_is_empty(Set3))
  	     end)}].
  
  -spec lid_test_() -> any().
  
negative.code: -define(RET_NORMAL, 0).
  -define(RET_INTERNAL_ERROR, 1).
  -define(RET_HEISENBUG, 2).
  -define(RET_INSTR_ERROR, 3).
  
  %% Debug messages (TODO: define externally?).
  %% -define(DEBUG, true).
  