Thursday, July 3, 2008

JPA Unit Testing

Up until now, I have been testing my stamp services using a test-schema that lives on my MySQL server. This server is remote (well in my basement connected to a 100Mb ethernet). While this has worked well for me, as the number of unit tests have increased in my code, the time of the tests is also increasing. Eskatos's wrote a great little blog article which introduced HSQLDB to my vernacular (see Unit test JPA Entities with in-memory database). Of course in his scenario, hibernate was used in place of Toplink. However I was intrigued by the idea of using a in-memory only database for unit tests. So I set about to get my unit tests to run. This turned out to be tricky to get working using Toplink. The first issue I ran into was that the tables refused to be created on startup. It turns out, this is due to an issue with the property missing from the persistence.xml file. This was outlined in a useful blog TopLink JPA and HSQLDB Quirk.

Even after making these changes however, I still could not get toplink to properly create the tables. It turns out, I had several entity beans which had name fields defined as unique=true. This caused the UNIQUE keyword to be written in the CREATE TABLE statements by Toplink which appears to be an invalid syntax for the HSQLDB database. After removing this JPA constraint from the affected objects I was able to successfully create the tables and run my tests. I also had some minor refactoring to do in some SQL utilities to leverage the persistenceUnit configuration, but I was very impressed with the speed.

Overall, my test suite went from executing in approximately eighteen seconds down to just four. While eighteen seconds may not seem like a long time, it was sufficiently long to disrupt my work efficiency. I decided to retain my MySQL peristence unit (for occasional "live" DB testing), and have now configured two test targets in Eclipse which take a org.javad.jpa.serviceName environment variable to switch between the hsqldb and toplink-test persistence units.

The final activity I will have left to do, is to determine a way to reinsert the unique statements in my entity beans without have the SQL generated for HSQLDB. There are a few threads out there, so I should be able to come up with something.

Finally, here is my persistence unit configuration for the HSQLDB database:
<persistence-unit name="hsqldb" transaction-type="RESOURCE_LOCAL">
    <property name="toplink.jdbc.user" value="sa"/>
    <property name="toplink.jdbc.password" value=""/>
    <!-- <property name="toplink.logging.level" value="FINEST"/> -->
    <property name="toplink.jdbc.url" value="jdbc:hsqldb:mem:."/>
    <property name="toplink.jdbc.driver" value="org.hsqldb.jdbcDriver"/>
    <property name="toplink.ddl-generation" value="create-tables"/>
    <property name="" value="HSQL"/>


Doug said...


You should try upgrading to EclipseLink from TopLink Essentials. I can't guarantee the problem with unique is resolved but that is where the developers are actively working. If the problem still exists please file a bug and we'll get it resolved for you.


Jason Drake said...

Thanks for the comment. Since I am not particularly tied to a JPA implementation, I will look into it. To be honest I chose to use Toplink Essentials over Hibernate partially for the deployment ease (there are a lot less JARs to deal with).