public void UncashedValuesTestTest(object value)
 {
     var expression = new ConstantExpression(value);
     var processor = CreateProcessor(expression);
     var result = processor.Evaluate(new SimpleProcessingStrategy());
     Assert.AreEqual(value, result.Values.First());
 }
 private IEnumerable<Cell> GetCells(int maxColumn, int cellCount)
 {
     var parser = _parserFactory(_textReader);
     for (var i = 0; i < cellCount; i++)
     {
         IExpression expression;
         try
         {
             expression = parser.ReadExpression();
         }
         catch (SpreadsheetException exception)
         {
             expression = new ConstantExpression(exception);
         }
         yield return new Cell(new CellAddress(i / maxColumn, i % maxColumn), 
                               expression ?? new ConstantExpression(null));
     }
     
 }