public void SimmetricSquareMatrix_Add_SimmetricSquareMatrix()
        {
            int[,] inputMatrixFirst = { { 4, 2, 3 }, { 2, 2, 5 }, { 3, 5, 2 } };

            BaseMatrix <int> firstMatrix = new SimmetricSquareMatrix <int>(inputMatrixFirst);

            BaseMatrix <int> secondMatrix = new SimmetricSquareMatrix <int>(inputMatrixFirst);

            var resultSumm = firstMatrix.Add(secondMatrix);

            int[,] resultMatrix = { { 8, 4, 6 }, { 4, 4, 10 }, { 6, 10, 4 } };

            var resultHelper = new SimmetricSquareMatrix <int>(resultMatrix);

            var helper = new HelperForSumm <int>();

            Assert.IsTrue(helper.IsEqual(resultHelper, resultSumm));
        }