public void DiagonalMatrixInsert_ValidIntFormat_ValidResult() { int[,] arr = new int[, ] { { 0, 0, 0 }, { 0, 3, 0 }, { 0, 0, 5 } }; DiagonalMatrix <int> sm = new DiagonalMatrix <int>(3, arr); sm.InsertElement(2, 2, 2); sm.InsertElement(1, 1, 9); Assert.AreEqual(arr[2, 2], 2); Assert.AreEqual(arr[1, 1], 9); }