public void Calculate_SpreadsheetWithoutCellReferences_AllCellsCalculated()
        {
            _spreadsheet.SetSize(2, 3);

            for (var row = 1; row <= _spreadsheet.RowsCount; row++)
            {
                for (var col = 1; col <= _spreadsheet.ColumnsCount; col++)
                {
                    _spreadsheet.SetValue(col, row, $"{col} + {row}");
                }
            }

            _spreadsheet.Calculate();

            for (var row = 1; row <= _spreadsheet.RowsCount; row++)
            {
                for (var col = 1; col <= _spreadsheet.ColumnsCount; col++)
                {
                    var cell = _spreadsheet.GetValue(col, row);

                    Assert.Equal(col + row, int.Parse(cell.ResultValue));
                }
            }
        }
        public void GetCell_CellIsOutOfSpreadsheetBoundaries_ThrowIndexOutOfRangeException(int columnNumber, int rowNumber)
        {
            _spreadsheet.SetSize(1, 1);

            Assert.Throws <IndexOutOfRangeException>(() => _spreadsheet.GetValue(rowNumber, columnNumber));
        }