def test_book_balance_is_sum_of_account_balances():
book = Book(code=uuid.uuid4().hex, name="New Book")
account_1 = Account(name="Test Account 1", initial_balance=10)
account_2 = Account(name="Test Account 2", initial_balance=20)
book.register(account_1)
book.register(account_2)
assert book.balance == account_1.balance + account_2.balance
def test_can_add_book_with_with_mapping(session):
book = Book(code=uuid.uuid4().hex, name="New Book")
account = Account(name="Test Account")
book.register(account)
session.add(book)
session.commit()
account = session.query(Account).one()
assert account.book == book
def test_can_register_account_in_book_only_once(account):
book = Book(code=uuid.uuid4().hex, name="New Book")
book.register(account)
book.register(account)
assert len(book.accounts) == 1
def test_can_register_account_in_book(account):
book = Book(code=uuid.uuid4().hex, name="New Book")
book.register(account)
assert account in book.accounts