public void SummingMatrices_CorrectParams_ExpectedResult() { int[,] arr1 = { { 1, 2 }, { 2, 4 } }; SymmetricMatrix <int> m1 = new SymmetricMatrix <int>(arr1); int[,] arr2 = { { 1, 2, 3 }, { 1, 2, 3 }, { 1, 2, 3 } }; SquareMatrix <int> m2 = new SquareMatrix <int>(arr2); Matrix <int> matrix = m1.SumMatrices(m2); int expected = 6; int actual = matrix[1, 1]; Assert.AreEqual(expected, actual); }