public void EmptyMonthlySummaryList()
        {
            IAverageMonthCalculator calculator = new AverageMonthCalculator();

            Assert.False(calculator.TryGetAverageMonth(null, out MonthlySummary averageMonth));
            Assert.Null(averageMonth);
        }
        public void TestAverageMonth(long[] totalIncomePerMonth, long expectedAverageIncome, long[] totalExpensesPerMonth, long expectedAverageExpenses)
        {
            ICollection <MonthlySummary> months = new List <MonthlySummary>();

            for (int i = 0; i < totalIncomePerMonth.Length; i++)
            {
                MonthlySummary monthlySummary = new MonthlySummary()
                {
                    Income = totalIncomePerMonth[i],
                    Spent  = totalExpensesPerMonth[i]
                };
                months.Add(monthlySummary);
            }

            IAverageMonthCalculator calculator = new AverageMonthCalculator();

            Assert.True(calculator.TryGetAverageMonth(months, out MonthlySummary averageMonth));
            Assert.NotNull(averageMonth);
            Assert.Equal(expectedAverageIncome, averageMonth.Income);
            Assert.Equal(expectedAverageExpenses, averageMonth.Spent);
        }