def test_interest():
"""
@todo These tests cannnot go to Production without making them robust to leap years, which you could do simply by
turning down the precision on assert_almost_equals: keeping the precision would require pretty rococo test code
"""
bank = Bank()
one_year_ago = datetime.today() - timedelta(days = 365)
two_years_ago = one_year_ago - timedelta(days = 365)
# first customer with checking account
bank.add_customer("Bill").open_account('Checking', 100.0, two_years_ago) # 10 ¢ interest
expected_interest = 100* (pow(1 + 1./365000, 730) - 1)
assert_almost_equal(expected_interest, bank.total_interest_paid)
# second customer with savings account
bank.add_customer("Jill").open_account('Savings', 1500.0, one_year_ago) # $2 interest
expected_interest += 1500 * (pow(1 + (4./3)/365000, 365) - 1)
assert_almost_equal(expected_interest, bank.total_interest_paid)
# third customer with maxi savings account
phil = bank.add_customer("Phil")
maxi_savings_account = phil.open_account('Maxi Savings', 3000, datetime.today() - timedelta(days = 30))
expected_interest_plus_30_days_maxi = expected_interest + 3000 * (pow(1 + 50./365000, 30) - 1)
assert_almost_equal(expected_interest_plus_30_days_maxi, bank.total_interest_paid)
# third customer's maxi savings account suffers a withdrawal
maxi_savings_account.withdraw(2000, datetime.today() - timedelta(days = 20))
# 3000@10 days maxi interest, 1000@10 days mini interest, 1000@10 days maxi interest
maxi_interest = 3000 * (pow(1 + 50./365000, 10) - 1)
maxi_interest += (1000 + maxi_interest) * (pow(1 + 1./365000, 10) - 1)
maxi_interest += (1000 + maxi_interest) * (pow(1 + 50./365000, 10) - 1)
expected_interest += maxi_interest
assert_almost_equal(expected_interest, bank.total_interest_paid)
# third customer has two accounts
phil.open_account('Checking', 100.0, datetime.today() - timedelta(days = 30))
expected_interest += 100* (pow(1 + 1./365000, 30) - 1)
assert_almost_equal(expected_interest, bank.total_interest_paid)
def test_customer_summary():
bank = Bank()
bank.add_customer('John').open_account('Checking')
assert_equals("Customer Summary\n - John (1 account)", bank.customer_summary)
