public void Mortgage_Constructor_TermMonths()
{
// Arrange
const int term = 5;
const TermUnits termUnits = TermUnits.Years;
const decimal principal = 100000M;
const decimal annualPercentInterest = 6.0M;
const decimal expectedMonthlyPercentInterest = 0.5M;
const int expectedTermMonths = 60;
// Act
var mortgage = new Mortgage
{
Principal = principal,
AnnualPercentInterest = annualPercentInterest,
Term = term,
TermUnits = termUnits
};
// Assert
Assert.AreEqual(principal, mortgage.Principal);
Assert.AreEqual(term, mortgage.TermYears);
Assert.AreEqual(expectedTermMonths, mortgage.TermMonths);
Assert.AreEqual(expectedMonthlyPercentInterest, mortgage.MonthlyPercentInterest);
}
public void Mortgage_CalculateMonthlyPayment()
{
// Arrange
const int term = 5;
const TermUnits termUnits = TermUnits.Years;
const decimal principal = 100000M;
const decimal annualPercentInterest = 6.0M;
const decimal expectedMonthlyPayment = 1933.28M;
var mortgage = new Mortgage
{
Principal = principal,
AnnualPercentInterest = annualPercentInterest,
Term = term,
TermUnits = termUnits
};
// Act
decimal monthlyPayment = mortgage.CalculateMonthlyPayment();
// Assert
Assert.AreEqual(expectedMonthlyPayment, monthlyPayment);
}
// POST api/monthlypayment
public decimal Post(Mortgage mortgage)
{
return mortgage.CalculateMonthlyPayment();
}
// POST api/amortization
public IEnumerable<MortgagePayment> Post(Mortgage mortgage)
{
return mortgage.GetAmortizationSchedule();
}
public void Mortgage_GetAmortizationTable()
{
// Arrange
const int term = 4;
const TermUnits termUnits = TermUnits.Months;
const decimal principal = 100005M;
const decimal annualPercentInterest = 6.0M;
const decimal monthlyPayment = 25314.54M;
var mortgage = new Mortgage
{
Principal = principal,
AnnualPercentInterest = annualPercentInterest,
Term = term,
TermUnits = termUnits
};
var expectedAmortizationSchedule =
new List<MortgagePayment>
{
new MortgagePayment
{
Index = 0,
PaymentAmount = monthlyPayment,
Balance = 75190.48M,
Interest = 500.02M,
Principal = 24814.52M,
TotalInterest = 500.02M,
TotalPrincipal = 24814.52M
},
new MortgagePayment
{
Index = 1,
PaymentAmount = monthlyPayment,
Balance = 50251.89M,
Interest = 375.95M,
Principal = 24938.59M,
TotalInterest = 875.97M,
TotalPrincipal = 49753.11M
},
new MortgagePayment
{
Index = 2,
PaymentAmount = monthlyPayment,
Balance = 25188.61M,
Interest = 251.26M,
Principal = 25063.28M,
TotalInterest = 1127.23M,
TotalPrincipal = 74816.39M
},
new MortgagePayment
{
Index = 3,
PaymentAmount = monthlyPayment + 0.01M,
Balance = 0.00M,
Interest = 125.94M,
Principal = 25188.61M,
TotalInterest = 1253.17M,
TotalPrincipal = 100005M
}
};
// Act
List<MortgagePayment> actualAmortizationSchedule = mortgage.GetAmortizationSchedule();
// Assert
int maxLoopIndex = Math.Max(actualAmortizationSchedule.Count, expectedAmortizationSchedule.Count);
for (int index = 0; index < maxLoopIndex; index++)
{
MortgagePayment expected = expectedAmortizationSchedule[index];
MortgagePayment actual = actualAmortizationSchedule[index];
Assert.AreEqual(expected.Index, actual.Index);
Assert.AreEqual(expected.Interest, actual.Interest);
Assert.AreEqual(expected.PaymentAmount, actual.PaymentAmount);
Assert.AreEqual(expected.Principal, actual.Principal);
Assert.AreEqual(expected.Balance, actual.Balance);
Assert.AreEqual(expected.TotalInterest, actual.TotalInterest);
Assert.AreEqual(expected.TotalPrincipal, actual.TotalPrincipal);
}
if (maxLoopIndex < actualAmortizationSchedule.Count)
{
Assert.Fail("Unexpected mortgage payment index " + actualAmortizationSchedule[maxLoopIndex].Index);
}
if (maxLoopIndex > actualAmortizationSchedule.Count)
{
Assert.Fail("Missing mortgage payment index " + expectedAmortizationSchedule[maxLoopIndex].Index);
}
}