public void AmortizeThirtyPaymentLoanWithAdditionalPaymentsTest()
{
//Amortize a loan with a 30 payments plus additional payments which result in the principal being paid off in 21 payments
//Test data computed by '30 Payment LoanWith Additional Payments.xlsx'
List<Payment> expectedPayments = CreateLoanPayments(
new[]
{
new[] {1m, 0.61m, 10.00m, 1.00m, 98.39m},
new[] {2m, 0.77m, 9.84m, 1.00m, 96.62m},
new[] {3m, 0.95m, 9.66m, 1.00m, 94.67m},
new[] {4m, 1.14m, 9.47m, 1.00m, 92.53m},
new[] {5m, 1.36m, 9.25m, 1.00m, 90.17m},
new[] {6m, 1.59m, 9.02m, 1.00m, 87.58m},
new[] {7m, 1.85m, 8.76m, 1.00m, 84.73m},
new[] {8m, 2.14m, 8.47m, 1.00m, 81.59m},
new[] {9m, 2.45m, 8.16m, 1.00m, 78.14m},
new[] {10m, 2.80m, 7.81m, 1.00m, 74.34m},
new[] {11m, 3.18m, 7.43m, 1.00m, 70.16m},
new[] {12m, 3.59m, 7.02m, 1.00m, 65.57m},
new[] {13m, 4.05m, 6.56m, 1.00m, 60.52m},
new[] {14m, 4.56m, 6.05m, 1.00m, 54.96m},
new[] {15m, 5.11m, 5.50m, 1.00m, 48.85m},
new[] {16m, 5.72m, 4.89m, 1.00m, 42.13m},
new[] {17m, 6.40m, 4.21m, 1.00m, 34.73m},
new[] {18m, 7.14m, 3.47m, 1.00m, 26.59m},
new[] {19m, 7.95m, 2.66m, 1.00m, 17.64m},
new[] {20m, 8.85m, 1.76m, 1.00m, 7.79m},
new[] {21m, 7.79m, 0.78m, 0m, 0.00m}
}
);
var loan = new AmortizedLoan
{
NumPayments = 30,
Principal = 100,
InterestRate = 0.10m,
AdditionalPayment = 1m
};
List<Payment> payments = loan.Amortize(Currency.UsDollars);
DumpPayments(payments);
VerifyPayments(expectedPayments, payments, Currency.UsDollars, 0.01m);
}
public void AmortizeTwelvePaymentWithCompundingEveryOtherPaymentLoanTest()
{
//Amortize a loan with a 12 payments with compounding every other payment
//Test data computed by '10 Payment Loan With Compounding Every Other Payment.xlsx'
var loan = new AmortizedLoan
{
NumPayments = 12,
Principal = 100,
InterestRate = 0.10m,
PaymentsPerCompounding = 2
};
List<Payment> payments = loan.Amortize(Currency.UsDollars);
List<Payment> expectedPayments = CreateLoanPayments(
new[]
{
new[] {1m, 7.96m, 0.83m, 0m, 92.04m},
new[] {2m, 8.03m, 0.76m, 0m, 84.01m},
new[] {3m, 8.09m, 0.7m, 0m, 75.92m},
new[] {4m, 8.16m, 0.63m, 0m, 67.76m},
new[] {5m, 8.23m, 0.56m, 0m, 59.53m},
new[] {6m, 8.3m, 0.49m, 0m, 51.23m},
new[] {7m, 8.36m, 0.43m, 0m, 42.87m},
new[] {8m, 8.43m, 0.36m, 0m, 34.44m},
new[] {9m, 8.5m, 0.29m, 0m, 25.94m},
new[] {10m, 8.57m, 0.22m, 0m, 17.37m},
new[] {11m, 8.65m, 0.14m, 0m, 8.72m},
new[] {12m, 8.72m, 0.07m, 0m, 04m},
}
);
DumpPayments(payments);
VerifyPayments(expectedPayments, payments, Currency.UsDollars, 0.01m);
}
private static void AmortizeSimpleThirtyPaymentLoanTestInternal(Currency currency,
List<Payment> expectedPayments,
decimal acceptableError)
{
var loan = new AmortizedLoan
{
NumPayments = 30,
Principal = 100,
InterestRate = 0.10m
};
List<Payment> payments = loan.Amortize(currency);
DumpPayments(payments);
VerifyPayments(expectedPayments, payments, currency, acceptableError);
}
public void AmortizeSimpleThreePaymentWithHugeAdditionalPaymentLoanTest()
{
//Amortize a loan with a 3 payments and an additional payment so large the third
//payment isn't necessary
//Test data computed by '3 Payment Loan With huge Additional Payment.xlsx'
var loan = new AmortizedLoan
{
NumPayments = 3,
Principal = 100,
InterestRate = 0.10m,
AdditionalPayment = 50
};
List<Payment> payments = loan.Amortize(Currency.UsDollars);
List<Payment> expectedPayments = CreateLoanPayments(
new[]
{
new[] {1m, 30.21m, 10.0m, 50m, 19.79m},
new[] {2m, 19.79m, 1.98m, 0m, 0m}
}
);
DumpPayments(payments);
VerifyPayments(expectedPayments, payments, Currency.UsDollars, 0.01m);
}
public void AmortizeTenPaymentWithIrregularAdditionalPaymentLoanTest()
{
//Amortize a loan with a 10 payments but sprinkle in some irregular additional
//payments
//Test data computed by '10 Payment Loan With Irregular Additional Payment.xlsx'
var loan = new AmortizedLoan
{
NumPayments = 10,
Principal = 100,
InterestRate = 0.10m
};
var additionalPayments = new[]
{
new AdditionalPayment() { Ordinal = 3, Amount = 10},
new AdditionalPayment() { Ordinal = 5, Amount = 1},
new AdditionalPayment() { Ordinal = 6, Amount = 10}
};
List<Payment> payments = loan.Amortize(Currency.UsDollars, additionalPayments);
List<Payment> expectedPayments = CreateLoanPayments(
new[]
{
new[] {1m, 6.27m, 10.0m, 0m, 93.73m},
new[] {2m, 6.90m, 9.37m, 0m, 86.83m},
new[] {3m, 7.59m, 8.68m, 10m, 69.24m},
new[] {4m, 9.35m, 6.92m, 0m, 59.89m},
new[] {5m, 10.28m, 5.99m, 1m, 48.61m},
new[] {6m, 11.41m, 4.86m, 10m, 27.20m},
new[] {7m, 13.55m, 2.72m, 0m, 13.65m},
new[] {8m, 13.65m, 1.37m, 0m, 0m}
}
);
DumpPayments(payments);
VerifyPayments(expectedPayments, payments, Currency.UsDollars, 0.01m);
}
public void AmortizeSimpleThreePaymentWithAdditionalPaymentLoanTest()
{
//Amortize a loan with a 3 payments
//Test data computed by 'Simple 3 Payment Loan With Additional Payment.xlsx'
var loan = new AmortizedLoan
{
NumPayments = 3,
Principal = 100,
InterestRate = 0.10m,
AdditionalPayment = 5
};
List<Payment> payments = loan.Amortize(Currency.UsDollars);
List<Payment> expectedPayments = CreateLoanPayments(
new[]
{
new[] {1m, 30.21m, 10.0m, 5m, 64.79m},
new[] {2m, 33.73m, 6.48m, 5m, 26.06m},
new[] {3m, 26.06m, 2.61m, 0m, 0.0m},
}
);
DumpPayments(payments);
VerifyPayments(expectedPayments, payments, Currency.UsDollars, 0.01m);
}
public void AmortizeSimpleThreePaymentLoanTest()
{
//Amortize a loan with a 3 payments
//Test data computed by 'Simple 3 Payment Loan.xlsx'
var loan = new AmortizedLoan
{
NumPayments = 3,
Principal = 100,
InterestRate = 0.10m
};
List<Payment> payments = loan.Amortize(Currency.UsDollars);
List<Payment> expectedPayments = CreateLoanPayments(
new[]
{
new[] {1, 30.21m, 10.0m, 69.79m},
new[] {2, 33.23m, 6.98m, 36.56m},
new[] {3, 36.56m, 3.66m, 0.0m},
}
);
VerifyPayments(expectedPayments, payments, Currency.UsDollars, 0.01m);
}
public void AmortizeSinglePaymentWithAdditionalPaymentLoanTest()
{
//Amortize a loan with a single payment that includes an additional payment amount
//Test data computed by 'Single Payment Loan.xlsx'
var loan = new AmortizedLoan
{
NumPayments = 1,
Principal = 100,
InterestRate = 0.10m,
AdditionalPayment = 20m
};
//Since there's only the one payment which covers the debt in full, the additional payment
//is not applied
List<Payment> payments = loan.Amortize(Currency.UsDollars);
Assert.AreEqual(1, payments.Count);
Assert.AreEqual(1, payments[0].Ordinal);
Assert.AreEqual(100, payments[0].Principal);
Assert.AreEqual(10, payments[0].Interest);
Assert.AreEqual(0, payments[0].AdditionalPayment);
Assert.AreEqual(0m, payments[0].OutstandingPrincipal);
}
public void AmortizeSinglePaymentLoanTest()
{
//Amortize a loan with a single payment
//Test data computed by 'Single Payment Loan.xlsx'
var loan = new AmortizedLoan
{
NumPayments = 1,
Principal = 100,
InterestRate = 0.10m
};
List<Payment> payments = loan.Amortize(Currency.UsDollars);
Assert.AreEqual(1, payments.Count);
Assert.AreEqual(1, payments[0].Ordinal);
Assert.AreEqual(100, payments[0].Principal);
Assert.AreEqual(10, payments[0].Interest);
Assert.AreEqual(0, payments[0].OutstandingPrincipal);
}
public void AmortizeEmptyLoanTest()
{
var loan = new AmortizedLoan();
loan.Amortize(Currency.UsDollars);
}