anchor.diff:      ].
   
   integral_test_() ->
  -    [?_assertEqual(pseudo_series([1,2,3]), evaluate_call(<<"integral">>, [pseudo_series([1,1,1])], 0, 0, 0)),
  -     ?_assertEqual(pseudo_series([1,null,2,3]), evaluate_call(<<"integral">>, [pseudo_series([1,null,1,1])], 0, 0, 0)),
  -     ?_assertEqual(pseudo_series([]), evaluate_call(<<"integral">>, [pseudo_series([])], 0, 0, 0)),
  -     ?_assertEqual(pseudo_series([null,null]), evaluate_call(<<"integral">>, [pseudo_series([null,null])], 0, 0, 0))
  +    [?_assertEqual([pseudo_series([1,2,3])], evaluate_call(<<"integral">>, [[pseudo_series([1,1,1])]], 0, 0, 0)),
  +     ?_assertEqual([pseudo_series([1,null,2,3])], evaluate_call(<<"integral">>, [[pseudo_series([1,null,1,1])]], 0, 0, 0)),
  +     ?_assertEqual([pseudo_series([])], evaluate_call(<<"integral">>, [[pseudo_series([])]], 0, 0, 0)),
  +     ?_assertEqual([pseudo_series([null,null])], evaluate_call(<<"integral">>, [[pseudo_series([null,null])]], 0, 0, 0))
       ].
   
   offset_to_zero_test_() ->
  -    Series = pseudo_series([102, 101, 104, 101, 100, 111]),
  -    Expected = pseudo_series([2, 1, 4, 1, 0, 11]),
  +    Series = [pseudo_series([102, 101, 104, 101, 100, 111])],
  +    Expected = [pseudo_series([2, 1, 4, 1, 0, 11])],
       [?_assertEqual(Expected, evaluate_call(<<"offsetToZero">>, [Series], 0, 0, 0))].
   
   sort_non_null_test_() ->
  
positive.code:     end.
  
  
  safe_minimum([]) -> null;
  safe_minimum(Values) ->
      safe_minimum(Values, null).
  
negative.code:     [?_assertEqual(10, gcd(10, 0)),
       ?_assertEqual(5, gcd(0, 5)),
       ?_assertEqual(5, gcd(10, 5))
      ].
  
  consolidate_test_() ->
      Series = pseudo_series([1,2,1,2,1,2,1,5]),
      Expected = pseudo_series([1.5,1.5,1.5,3.0], 20),
      [?_assertEqual(Expected, consolidate(Series, 2)),
       ?_assertEqual(pseudo_series([1.5], 30), consolidate(pseudo_series([1, null, 2]), 3)),
       ?_assertEqual(pseudo_series([1.5, 1.0], 30), consolidate(pseudo_series([1, null, 2, null, null, 1]), 3)),
       ?_assertEqual(pseudo_series([], 20), consolidate(pseudo_series([]), 2))
      ].
  
  percentile_test_() ->
  