public void TestDecimal()
        {
            decimal[] arr = new decimal[] { 1.1m, 2.1m, -22.2344455m };
            var       res = QuickSortDualPivot.Sort((decimal[])arr.Clone(), 0, arr.Length - 1);

            Assert.Equal(arr.OrderBy(x => x), res);
        }
        public void Test <T>(T[] arr) where T : struct, IComparable <T>
        {
            var res = QuickSortDualPivot.Sort((T[])arr.Clone(), 0, arr.Length - 1);

            Assert.Equal(arr.OrderBy(x => x), res);
        }
        public void TestNull()
        {
            var res = QuickSortDualPivot.Sort((decimal[])null, 0, 0);

            Assert.Null(res);
        }