public void CalculateCashFlows_Should_be_passed_when_testing_npv_amount_for_given_inputs()
{
// Arrange
NpvInput input = new NpvInput();
input.Cash = 100m;
input.CashSeries = 10m;
input.IncrementDiscountRate = 0.25m;
input.LowerDiscountRateBound = 1m;
input.UpperDiscountRateBound = 15m;
NpvCalculatorController controller = new NpvCalculatorController(new NpvCalculator());
// Act
IList <NpvCashFlow> npvCashFlows = controller.CalculateCashFlows(input);
// Assert
var npvCashFlow = npvCashFlows.Where(c => c.Rate == 0.01m).SingleOrDefault <NpvCashFlow>();
var npvCashFlow2 = npvCashFlows.Where(c => c.Rate == 0.1m).SingleOrDefault <NpvCashFlow>();
var npvCashFlow3 = npvCashFlows.Where(c => c.Rate == 0.15m).SingleOrDefault <NpvCashFlow>();
Assert.IsTrue(npvCashFlows.Count() > 0);
Assert.IsTrue(Math.Round(npvCashFlow.Amount, 2) == 947.13m);
Assert.IsTrue(Math.Round(npvCashFlow2.Amount, 2) == 614.46m);
Assert.IsTrue(Math.Round(npvCashFlow3.Amount, 2) == 501.88m);
}
public IList <NpvCashFlow> CalculateCashFlows(NpvInput input)
{
// cash series flows
List <double> flows = new List <double>();
for (int i = 0; i < input.CashSeries; i++)
{
flows.Add(Convert.ToDouble(input.Cash));
}
// calc npv base on rate and cash series flows
var result = new List <NpvCashFlow>();
decimal rate = input.LowerDiscountRateBound;
while (rate <= input.UpperDiscountRateBound)
{
double npv = flows.Select((c, n) => c / Math.Pow(1 + Convert.ToDouble(rate), n + 1)).Sum();;
result.Add(new NpvCashFlow {
Rate = rate, Amount = Convert.ToDecimal(npv)
});
rate = rate + input.IncrementDiscountRate;
}
;
return(result);
}
public IList <NpvCashFlow> CalculateCashFlows(NpvInput input)
{
// turn percentage to decimal.
// TO DO : move this to front end if time allows
input.LowerDiscountRateBound = input.LowerDiscountRateBound / 100;
input.UpperDiscountRateBound = input.UpperDiscountRateBound / 100;
input.IncrementDiscountRate = input.IncrementDiscountRate / 100;
var result = _npvCalculator.CalculateCashFlows(input);
return(result);
}
