Using the Transaction Script pattern - POJOs in Action: Developing Enterprise Applications with Lightweight Frameworks - page 330

Similarly, the delivery information parameters can be valid or invalid for a variety
of reasons. In order to flesh out and thoroughly test the transaction script, we
must write tests for several combinations of arguments. Let's look a test for the
scenario where updateDeliveryInfo() is invoked with a null pending order ID
and valid delivery information.
In this scenario, updateDeliveryInfo() fulfills its responsibilities as follows:

Creates the PendingOrder —It can call PendingOrderDAO.createPending-
Order() .

1

Verifies that the delivery time in the future —It can do this with some simple
conditional logic.

2

Finds the available restaurants —It can retrieve the available restaurants by
calling the RestaurantDAO , which defines a findAvailableRestaurants()
method. This method returns the list of restaurants that serve the speci-
fied delivery information.

3

Stores the delivery information in the PendingOrder — updateDeliveryInfo() can
do this by simply calling setters on the PendingOrderDTO . Remember that
unlike the PendingOrder domain object, the PendingOrderDTO does not
implement any business logic and so doesn't validate the data that it contains.

4

Saves it in the database —It saves the PendingOrder in the database by calling
PendingOrderDAO.savePendingOrder() , which updates the PENDING_OR-
DER table.

5

Returns an UpdateDeliveryInfoResult that contains the updated Pending-
Order and the available restaurants —It creates the UpdateDeliveryInfo-
Result by calling new .

6

We can write a test that verifies that updateDeliveryInfo() does this by using
mock objects for the PendingOrderDAO , RestaurantDAO , and PendingOrderDTO . The
test configures these mock objects to expect particular methods to be called and
return test values, and passes the mock DAO s to PlaceOrderTransaction-
ScriptsImpl as constructor arguments. It then calls the transaction script and ver-
ifies that it returns the expected DTO . Listing 9.1 shows the test method.

Listing 9.1 PlaceOrderTransactionScriptsImplTests

public class PlaceOrderTransactionScriptsImplTests
extends MockObjectTestCase {

private Mock mockPendingOrderDAO;