public void CalculateOutputFormat_StartDateMonthDifferentEndDateMonth_DisplayMessage()
        {
            var startDate = DateTime.ParseExact("01.02.2017", "dd.MM.yyyy", CultureInfo.InvariantCulture);
            var endDate   = DateTime.ParseExact("15.03.2017", "dd.MM.yyyy", CultureInfo.InvariantCulture);

            var result = RangeCalculatorProgram.CalculateOutputFormat(startDate, endDate);

            StringAssert.Contains("01.02-15.03.2017", result);
        }
        public void CalculateOutputFormat_StartDateGreaterThenEndDate_ErrorMessage()
        {
            var startDate = DateTime.ParseExact("01.02.2017", "dd.MM.yyyy", CultureInfo.InvariantCulture);
            var endDate   = DateTime.ParseExact("15.01.2016", "dd.MM.yyyy", CultureInfo.InvariantCulture);

            var result = RangeCalculatorProgram.CalculateOutputFormat(startDate, endDate);

            StringAssert.Contains("Please contact support", result);
        }