public void AddWorkSheetsTest()
        {
            ExcelManager manager = new ExcelManager();

            manager.AddWorkSheets(new StringList {
                "Worksheet1", "Worksheet2"
            }, ExcelFile);

            try
            {
                //try to go on new worksheets
                manager.ChangeCellValue(ExcelFile, "Worksheet1", "A1", "Test");
                manager.ChangeCellValue(ExcelFile, "Worksheet2", "A1", "Test");
            }
            catch
            {
                Assert.Fail();
            }
        }