@Test
public void confirmingOrderEmptiesCart() throws Exception {
testee.addBookToCart(2);
testee.confirmOrder();
assertEquals(0, testee.getCart().getBookCount());
assertEquals(
asList(testee.findBookById(2)), testee.getCheckout().getConfirmedOrder().getBooks());
}
@Test
public void addBookToCart() throws Exception {
testee.addBookToCart(1);
assertEquals(1, testee.getCart().getBookCount());
assertEquals(asList(testee.findBookById(1)), testee.getCart().getBooks());
}