anchor.diff:  
   parses_a_string_containing_a_complex_number_test_() ->
       lists:map(fun({Input,Expected}) ->
  -                      ?_assertEqual(Expected, execute(Input, []))
  +                      assertComplexWithin(Expected, 0.000000001,  execute(Input, []))
                 end,
                 [ {"5,3", [{5,3}]},
                   {"-2.0e-3,5", [{-0.002,5}]},
  
positive.code: divides_two_numbers_test_() ->
      [
       ?_assertEqual([{0.7,-0.4}], execute("3,2 2,4 /",[])),
       ?_assertEqual([{1.5,1.0}],    execute("3,2 2   /",[])),
       ?_assertEqual([{0.3,-0.6}], execute("3   2,4 /",[])),
       ?_assertEqual([0.5],        execute("1   2   /",[]))
      ].
  
negative.code: 
  %%% Internal Functions
  
  assertComplexWithin([{ExpRe,ExpIm}], Tolerance, [{ActRe,ActIm}|_]) ->
      [ assertComplexWithin(ExpRe, Tolerance, ActRe), assertComplexWithin(ExpIm, Tolerance, ActIm) ];
  assertComplexWithin(Expected, Tolerance, Actual) ->
      io:format("Does ~p = ~p +/- ~p?~n", [Actual,Expected,Tolerance]),
      ?_assert(erlang:abs(Expected - Actual) =< Tolerance).
  
  assertWithin(Expected, Tolerance, [Actual|_]) ->
      io:format("Does ~p = ~p +/- ~p?~n", [Actual,Expected,Tolerance]),
      ?assert(erlang:abs(Expected - Actual) =< Tolerance ).
  
  %%% Unit Tests
  
  