def test_order_observers_regiester():
"""
The order in which two observers are registered should not affect
the update cycle.
"""
start = datetime.date(2020, 7, 4)
date = DateSubject(start)
end = date.date + datetime.timedelta(days=10)
bill_info = BillInfo(day=end.day, amount=Money(10.00))
loan_info = LoanInfo(Money(1000.00), interest=1.00)
loan = Loan(loan_info, bill_info)
loan_copy = copy.deepcopy(loan)
account = Account(Money(10000.00)) # a reserve of money
date.register(MinPaymentPayer(loan, account))
date.register(InterestAccruer(loan))
date.register(InterestAccruer(loan_copy))
date.register(MinPaymentPayer(loan_copy, account))
for d in date_range(start, end):
date.increment_day()
# \todo These are off by a penny. Is that acceptable?
assert almost_equal(loan.balance, loan_copy.balance, 0.01)
assert almost_equal(loan.total_owed, loan_copy.total_owed, 0.01)
def test_dont_overpay_small_balance_loan(current_date):
"""
If a loan has only a small balance left, and the
HighestInterestFirstPayer's amount is greater than that balance
do not overpay.
"""
init_account_balance = Money(10000.00)
account = Account(init_account_balance)
init_loan_balance = Money(100.00)
bill_info = BillInfo(
day=10, amount=Money(1.00)) # days after dates covered in this test
loan_info = LoanInfo(init_loan_balance, interest=1.00)
loans = [Loan(loan_info, bill_info)]
# pay day after current_date (5)
pay_amount = Money(200.00)
payer = HighestInterestFirstPayer(loans, account,
next_day(current_date.date), pay_amount)
init_total_owed = payer.total_owed
current_date.register(payer)
current_date.increment_day()
assert account.balance + init_loan_balance == init_account_balance
assert loans[0].total_owed == Money(0.00)
def test_highest_interest_accruing(current_date):
"""
If there are multiple loans, it's the highest interest loans who
are accruing that are addressed first.
"""
init_account_balance = Money(10000.00)
account = Account(init_account_balance)
init_loans = []
init_loan_balance = Money(100.00)
bill_info = BillInfo(
day=10, amount=Money(1.00)) # days after dates covered in this test
accrue_start_date = current_date.date + datetime.timedelta(days=100)
loan_info = LoanInfo(init_loan_balance, 1.00, accrue_start_date)
init_loans.append(Loan(loan_info, bill_info))
loan_info = LoanInfo(init_loan_balance, 1.00)
init_loans.append(Loan(loan_info, bill_info))
loans = copy.deepcopy(init_loans)
payer = HighestInterestFirstPayer(loans, account,
next_day(current_date.date),
Money(50.00))
current_date.register(payer)
current_date.increment_day()
# first loan, nonaccruing, should not have a changed balance
assert loans[0].balance == init_loans[0].balance
# second loan should have a decreased balance
assert loans[1].balance + Money(50.00) == init_loans[1].balance
def test_account_loan_balance_adjusts(current_date):
"""
The total_owed on a loan and change in account balance should
be changed in a specific way.
"""
init_account_balance = Money(10000.00)
account = Account(init_account_balance)
init_loan_balance = Money(100.00)
bill_info = BillInfo(
day=10, amount=Money(1.00)) # days after dates covered in this test
loan_info = LoanInfo(init_loan_balance, interest=1.00)
loans = [Loan(loan_info, bill_info)]
# pay day after current_date (5)
pay_amount = Money(10.00)
payer = HighestInterestFirstPayer(loans, account,
next_day(current_date.date), pay_amount)
init_total_owed = payer.total_owed
current_date.register(payer)
current_date.increment_day()
assert account.balance + pay_amount == init_account_balance
assert loans[0].total_owed + pay_amount == init_loan_balance
def test_highest_interest_first(current_date):
"""
If there are 2+ loans, the loan with highest interest
receives the payment.
"""
init_account_balance = Money(10000.00)
account = Account(init_account_balance)
init_loans = []
init_loan_balance = Money(100.00)
bill_info = BillInfo(
day=10, amount=Money(1.00)) # days after dates covered in this test
loan_info = LoanInfo(init_loan_balance, interest=1.00)
init_loans.append(Loan(loan_info, bill_info))
loan_info = LoanInfo(init_loan_balance, interest=loan_info.interest + 1.00)
init_loans.append(Loan(loan_info, bill_info))
loans = copy.deepcopy(init_loans)
payer = HighestInterestFirstPayer(loans, account,
next_day(current_date.date),
Money(100.00))
current_date.register(payer)
current_date.increment_day()
# second loan, the higher interest one, should have a different balance
assert init_loans[1].balance != loans[1].balance
# but lower interest one should be unchanged in this test
assert init_loans[0].balance == loans[0].balance
def test_nonzero_balance_loan(current_date):
"""
If there is a nonzero balance loan total owed of highinterestpayer
should change, and account amount should change.
"""
init_account_balance = Money(10000.00)
account = Account(init_account_balance)
bill_info = BillInfo(day=10, amount=Money(1.00))
loan_info = LoanInfo(Money(100.00), interest=1.00)
loans = [Loan(loan_info, bill_info)]
payer = HighestInterestFirstPayer(loans, account, 8, Money(10.00))
init_total_owed = payer.total_owed
current_date.register(payer)
for i in range(31):
current_date.increment_day()
assert init_account_balance != account.balance
assert init_total_owed != payer.total_owed
def test_multiple_loans_highest_interest_first(current_date):
"""
If there are 2+ loans, where payer's amount covers at least one of the
loan's remaining balance, and then some, the second highest interest
loan is the loan whose balance gets paid down.
"""
init_account_balance = Money(10000.00)
account = Account(init_account_balance)
init_loans = []
init_loan_balance = Money(100.00)
bill_info = BillInfo(
day=10, amount=Money(1.00)) # days after dates covered in this test
loan_info = LoanInfo(init_loan_balance, interest=1.00)
init_loans.append(Loan(loan_info, bill_info))
loan_info = LoanInfo(init_loan_balance, interest=loan_info.interest + 1.00)
init_loans.append(Loan(loan_info, bill_info))
loan_info = LoanInfo(init_loan_balance, interest=loan_info.interest - 0.50)
init_loans.append(Loan(loan_info, bill_info))
loans = copy.deepcopy(init_loans)
payer = HighestInterestFirstPayer(loans, account,
next_day(current_date.date),
init_loan_balance + Money(50.00))
current_date.register(payer)
current_date.increment_day()
# first loan in this test should remain unchanged.
assert loans[0].balance == init_loans[0].balance
# Second loan should have zero money left
assert loans[1].balance == Money(0.00)
# Third loan should have a reduced balance
assert loans[2].balance == init_loans[2].balance - Money(50.00)
def create_loan(accrue_start_date=None): # create loan where minimum payment is the day after ptest fixture's date. bill_info = BillInfo(day=20, amount=Money(1.00)) loan_info = LoanInfo(Money(10000.00), interest=1.00, start_date=accrue_start_date) return Loan(loan_info, bill_info)
def zero_accured_loan():
"""Return a loan with zero accrued interest with 1% interest rate (APR)"""
bill_info = BillInfo(day=1, amount=Money())
loan_info = LoanInfo(Money(100.00), interest=1.00)
return Loan(loan_info, bill_info)
def create_loan(initial_amount, min_payment, bill_start_date=None):
# create loan where minimum payment is the day after ptest fixture's date.
bill_info = BillInfo(day=5, amount=min_payment, start_date=bill_start_date)
loan_info = LoanInfo(initial_amount, interest=1.00)
return Loan(loan_info, bill_info)