### Question:
Order { @Nullable public Customer getCustomer() { return customer; } private  Order(Builder builder); String getId(); @Deprecated long getAmount(); String getCurrencyCode(); Date getPurchaseDate(); List<LineItem> getLineItems(); @Nullable String getCustomerOrderId(); @Nullable Customer getCustomer();  }### Answer:
@Test public void order_setCustomer_verify() { Order.Customer customer = mock(Order.Customer.class); Order order = new Order.Builder("123", new Date(), Collections.<Order.LineItem>emptyList()) .setCustomer(customer) .build(); assertEquals(order.getCustomer(), customer); }