Overview of persisting a domain model - POJOs in Action: Developing Enterprise Applications with Lightweight Frameworks - page 140

knowledge about the structure of the mapping document but does require the
ORM framework to expose the necessary API s. I describe how to write ORM tests in
more detail in chapters 5 and 6.

Mock object testing of repositories
We could test a repository using database-level tests. For example, one way to test
a repository method that executes a query is to populate data with test objects, call
the method, and verify that it returns the expected objects. The problem with this
approach is that it tests several things simultaneously: the repository, any queries
that it executes, and the O/R mapping. The test needs a lot of setup and executes
slowly. A better approach, which reduces the number of test cases and database
accesses, is to test the repository using mock objects and to test the queries against
the database separately.
Consider, for example, the PendingOrder.createPendingOrder() method, which
creates a PendingOrder in the database. One way to test this method is to write a test
that calls it and then verifies that it inserted a row into the PENDING_ORDER table.
However, if you have written tests for the object/relational mapping, then you can
safely assume that HibernateTemplate.save() or JdoTemplate.makePersistent()
will work as expected. The repository test does not need to verify that a PendingOrder
will be inserted into the PENDING_ORDER table when the repository calls save() or
makePersistent() . We can therefore simplify and speed up the repository test by
using a mock object for HibernateTemplate or JdoTemplate and verifying that the
repository calls save() or makePersistent() as expected. We can use a similar
approach to test other repository methods.

4.5.4 Overview of ORMUnit

In order to make it easier to write tests for the O/R mapping and persistent
objects, I've written a simple JU nit extension called ORMU nit. It provides several
base classes that extend JUnitTestCase :
■ HibernateMappingTests : For testing a Hibernate object/relational mapping
■ JDOMappingTests : For testing a JDO object/relational mapping
■ HibernatePersistenceTests : For testing Hibernate objects and queries

JDOPersistenceTests : For testing JDO objects and queries

■

HibernateMappingTests and JDOMappingTests simplify the task of testing the object/
relational mapping. They provide methods for making assertions about the map-
ping and for verifying that it matches the database schema. For example, they make
it easy to write a test that verifies that all of a class's fields are mapped to the database.