public void Test_SelectDCValues()
        {
            // generate random array
            int[,] input = ArrayHelper.GetTwoDimensionalArrayOfLength(16);
            // do the zick zack
            List <int[]> output = ZickZack.ZickZackSortChannel(input);

            // Action
            int[] expected = new[] { 0, 8, 128, 136 };
            int[] actual   = Coefficients.SelectDCValues(output);

            // Assertion
            actual.Should().BeEquivalentTo(expected);
        }