public CalculateNpvResponse CalculateNpv(CalculateNpvRequest request)
{
var result = new CalculateNpvResponse();
var discountDetail = request.DiscountRateDetail;
var noIncrement = discountDetail.IncrementPercentage == 0;
for (var discountPercentage = discountDetail.LowerBoundPercentage; discountPercentage <= discountDetail.UpperBoundPercentage; discountPercentage += discountDetail.IncrementPercentage)
{
var npvsForDiscount = CalculateNpvForDiscount(request.InitialInvestment, request.CashFlows, discountPercentage);
result.Add(new NpvResult
{
DiscountPercentage = discountPercentage,
PeriodNpvs = npvsForDiscount,
Npv = npvsForDiscount.LastOrDefault()
});
if (noIncrement)
{
break;
}
}
return(result);
}
public override void SetUp()
{
base.SetUp();
_validCalculateNpvRequest = new CalculateNpvRequest
{
CashFlows = new List <double> {
1000, 2000, 3000
},
DiscountRateDetail = DiscountRateDetailValidatorTests.CreateValidDiscountRateDetail(),
InitialInvestment = 10000
};
}
public IActionResult CalculateNpv([FromBody] CalculateNpvRequest request)
{
if (request == null || !ModelState.IsValid)
{
return(BadRequest(ModelState.GetFirstError() ?? GenericErrorMessage));
}
try
{
var result = _npvCalculator.CalculateNpv(request);
return(Ok(result));
}
catch
{
return(BadRequest(GenericErrorMessage));
}
}
public void CalculateNpv_ShouldCalculateNpvForDifferentDiscounts()
{
var request = new CalculateNpvRequest
{
InitialInvestment = 12000,
CashFlows = new List <double> {
2500, 4000, 5000, 3000, 1000
},
DiscountRateDetail = new DiscountRateDetail
{
LowerBoundPercentage = 1,
UpperBoundPercentage = 15,
IncrementPercentage = 0.25
}
};
var target = CreateTarget();
var result = target.CalculateNpv(request);
result.Should().HaveCount(57);
result.All(r => r.PeriodNpvs.Count == 5).Should().BeTrue();
var tolerance = 0.0001;
var firstResult = result.First();
firstResult.DiscountPercentage.Should().Be(1);
firstResult.PeriodNpvs.Last().Should().Be(firstResult.Npv);
firstResult.Npv.Should().BeApproximately(3083.7891, tolerance);
var midResult = result[23];
midResult.DiscountPercentage.Should().Be(6.75);
midResult.PeriodNpvs.Last().Should().Be(midResult.Npv);
midResult.Npv.Should().BeApproximately(993.8657, tolerance);
var lastResult = result.Last();
lastResult.DiscountPercentage.Should().Be(15);
lastResult.PeriodNpvs.Last().Should().Be(lastResult.Npv);
lastResult.Npv.Should().BeApproximately(-1301.4947, tolerance);
}
