anchor.diff:  
   set_test_() ->
        [{"Empty",
  -       ?_assert(set_is_empty(set_new()))},
  +       ?_assertEqual(true, set_is_empty(set_new()))},
         {"Add/remove one",
          ?_test(begin
   		  {Result, NewSet} = set_pop(set_add(set_new(), 42)),
   		  ?assertEqual(42, Result),
  -		  ?assert(set_is_empty(NewSet))
  +		  ?assertEqual(true, set_is_empty(NewSet))
   	      end)},
         {"Add/remove multiple",
         ?_test(begin
  
positive.code: %%%----------------------------------------------------------------------
  
  %% Instrument file Path and produce all interleavings of (Mod, Fun, Args).
  -spec analyze(string(), atom(), atom(), [any()]) -> 'true'.
  
  analyze(File, Mod, Fun, Args) ->
      case instr:instrument_and_load(File) of
  
negative.code: 	    log:log("~n"),
  	    interleave(Mod, Fun, Args);
  	error ->
  	    ?RET_INSTR_ERROR
      end.
  
  %% Produce all possible process interleavings of (Mod, Fun, Args).
  -spec interleave(atom(), atom(), [any()]) -> ?RET_NORMAL | ?RET_HEISENBUG.
  
  interleave(Mod, Fun, Args) ->
      register(sched, self()),
  