anchor.diff:  
   t_0_test() ->
     Filename = "redbug.txt",
  -  {_, _} = redbug:start("lists:sort", [{print_file,Filename},print_msec]),
  +  {_,_} = redbug:start("lists:sort",[{print_file,Filename},print_msec]),
     [1,2,3] = lists:sort([3,2,1]),
     timer:sleep(100),
     redbug:stop(),
  
positive.code: t_3_test() ->
    Filename = "redbug.txt",
    Pid = spawn(fun()->receive P when is_pid(P)->P!ding;quit->ok end end),
    {_,_} = redbug:start(send,[{procs,Pid},{print_file, Filename}]),
    Pid ! self(),
    timer:sleep(100),
    redbug:stop(),
  
negative.code: t_4_test() ->
    Filename = "redbug.txt",
    Pid = spawn(fun()->receive P when is_pid(P)->P!ding;quit->ok end end),
    {_,_} = redbug:start('receive',[{procs,Pid},{print_file,Filename}]),
    Pid ! pling,
    timer:sleep(100),
    redbug:stop(),
  