### Question:
MathUtils { public static List<Integer> negative(List<Integer> vals) { return vals.stream().filter(val -> val < 0).collect(Collectors.toList()); }  static Integer sum(List<Integer> vals); static List<Integer> positive(List<Integer> vals); static List<Integer> negative(List<Integer> vals);  }### Answer:
@Test @DisplayName("should get negative values") void negativeTest() { var negativeValues = MathUtils.negative(vals); assertEquals(negativeValues, List.of(-2, -1, -1)); }