anchor.diff:  format(Fmt, Args, Max, Options) ->
       try lager_format:format(Fmt, Args, Max, Options)
       catch
  -        _:_ ->
  +        _What:_Why ->
               erlang:error(badarg, [Fmt, Args])
       end.
   
  
positive.code: alist([], _Max, _Options) -> {"\"", 1};
  alist(_, Max, #print_options{force_strings=true}) when Max < 4 -> {"...", 3};
  alist(_, Max, #print_options{force_strings=false}) when Max < 5 -> {"...\"", 4};
  alist([H|T], Max, Options) when is_integer(H), H >= 16#20, H =< 16#7e ->     % definitely printable
      {L, Len} = alist(T, Max-1, Options),
      {[H|L], Len + 1};
  alist([H|T], Max, Options) when H =:= 9; H =:= 10; H =:= 13 ->
      {L, Len} = alist(T, Max-1, Options),
      case Options#print_options.force_strings of
          true ->
  
negative.code:     ?assertEqual("hello", lists:flatten(format("~s", [<<"hello">>], 50))),
      ?assertEqual("hello\nworld", lists:flatten(format("~s", [<<"hello\nworld">>], 50))),
      ?assertEqual("<<\"hello\\nworld\">>", lists:flatten(format("~p", [<<"hello\nworld">>], 50))),
      ?assertEqual("<<\"\\\"hello world\\\"\">>", lists:flatten(format("~p", [<<"\"hello world\"">>], 50))),
      ?assertEqual("<<\"hello\\\\world\">>", lists:flatten(format("~p", [<<"hello\\world">>], 50))),
      ?assertEqual("<<\"hello\\\\\world\">>", lists:flatten(format("~p", [<<"hello\\\world">>], 50))),
      ?assertEqual("<<\"hello\\\\\\\\world\">>", lists:flatten(format("~p", [<<"hello\\\\world">>], 50))),
      ?assertEqual("<<\"hello\\bworld\">>", lists:flatten(format("~p", [<<"hello\bworld">>], 50))),
      ?assertEqual("<<\"hello\\tworld\">>", lists:flatten(format("~p", [<<"hello\tworld">>], 50))),
      ?assertEqual("<<\"hello\\nworld\">>", lists:flatten(format("~p", [<<"hello\nworld">>], 50))),
      ?assertEqual("<<\"hello\\rworld\">>", lists:flatten(format("~p", [<<"hello\rworld">>], 50))),
      ?assertEqual("<<\"hello\\eworld\">>", lists:flatten(format("~p", [<<"hello\eworld">>], 50))),
      ?assertEqual("<<\"hello\\fworld\">>", lists:flatten(format("~p", [<<"hello\fworld">>], 50))),
      ?assertEqual("     hello", lists:flatten(format("~10s", [<<"hello">>], 50))),
      ok.
  
  