Testing database access - JUnit in Action - page 335

■ DELETE_ALL —Delete from the database all rows from each table present in the
dataset. Although it's an aggressive approach in many cases (such as when
the database is shared by many developers or it contains data that shouldn't
be deleted), it's the simplest way to guarantee the state of the database
(because sometimes the database might contain data that isn't deleted by
DELETE and hence can interfere in the test results).
■ TRUNCATE —Same purpose as DELETE_ALL , but faster, because it uses the SQL 's
TRUNCATE TABLE . The only drawback is that not all databases support such
SQL operation.
■ CLEAN_INSERT —Composite operation, first calls DELETE_ALL , then INSERT , using
the same dataset.
■ TRANSACTION(operation) —Not exactly a field but a method. It creates a Data-
baseOperation that will wrap another operation inside a database transaction.
It's particularly useful in cases where tables have circular dependency and rows
can't be inserted outside a transaction with deferred constraints.
■ CLOSE_CONNECTION(operation) —Another wrapper, it executes the operation
and then automatically closes the connection. This can be useful in tear-
down methods.
■ NONE —An empty operation that does nothing.
That's it; we wrote our first DbUnit test case and set the foundation for most of the
tests to come.

17.4 Asserting database state with datasets

Another common use of datasets is to assert that the database has the right data after
an insert or update. Back to our DAO example: we need a test case for the addUser()
method, and the workflow for this test is the opposite from getUserById() 's test.
Here we first create a User object, ask our DAO to persist it, then use a DbUnit dataset
to assert that the data was properly inserted. The code snippet in listing 17.7 is our
first attempt at such a test case.

Listing 17.7 Test case for addUser() method

[...]
import org.dbunit.Assertion;
[...]
public class UserDaoJdbcImplTest extends AbstractDbUnitTestCase {
[...]
@Test
public void testAddUser() throws Exception {
User user = new User();
user.setFirstName("Jeffrey");
user.setLastName("Lebowsky");
user.setUsername("ElDuderino");
long id = dao.addUser(user);
assertTrue(id>0);

B

C
D