public void EnergySaverCalculator_should_throw_exception_when_starting_date_after_expiration_date(int gas, int electricity, decimal initGasRate, decimal finalGasRate, decimal initElecRate, decimal finalElecRate, DateTime startingDate, DateTime expirationDate, decimal expected)
        {
            var energySaver = new AbstractCalculator(gas, electricity, initGasRate, finalGasRate, initElecRate, finalElecRate, startingDate, expirationDate);
            var annualCost  = energySaver.GetTotalAnnualCost();

            Assert.Equal(annualCost, expected);
        }
        public void SaveOnlineCalculator_should_output_correct_tariff(int gas, int electricity, decimal initGasRate, decimal finalGasRate, decimal initElecRate, decimal finalElecRate, DateTime startingDate, DateTime expirationDate, decimal expected)
        {
            var energySaver = new AbstractCalculator(gas, electricity, initGasRate, finalGasRate, initElecRate, finalElecRate, startingDate, expirationDate);
            var annualCost  = energySaver.GetTotalAnnualCost();

            Assert.Equal(annualCost, expected);
        }