CDI in JUnit tests with Jersey Test Framework

Question

We are using the Jersey Test Frameworks for API testing. In test-mode, we use an h2 database, mysql in production. Everything is fine to this point.

Now i want to write tests for our repositories to check if the data is written properly to the database.

I can't inject any classes in my tests so i am using the standard constructor the create an new instance of RepositoryA. Works for me.

Now the problem: RepositoryA is now injecting an instance of RepositoryB. And injection isn't working on test-scope.

Is it possible to get injection running in this environment?

Answer 1

Depending on the versions of the libraries you are using, running CDI in JUnit Test is different.

First you need to add this dependency, selecting the right version :

<dependency>
   <groupId>org.jboss.weld</groupId>
   <artifactId>weld-junit5</artifactId> // or weld-junit4
   <version>1.3.0.Final</version>
   <scope>test</scope>
</dependency>

Then you can enable Weld in your JUnit test. Here is an example of injecting a repository for an entity class called VideoGame :

@Slf4j
@EnableWeld
class VideoGameRepositoryTest
{
    @WeldSetup 
    private WeldInitiator weld = WeldInitiator.performDefaultDiscovery();

    @Inject
    private VideoGameRepository repo;

    @Test
    void test()
    {
        VideoGame videoGame = VideoGameFactory.newInstance();
        videoGame.setName("XENON");
        repo.save(videoGame);
        // testing if the ID field had been generated by the JPA Provider.
        Assert.assertNotNull(videoGame.getVersion());
        Assert.assertTrue(videoGame.getVersion() > 0);
       log.info("Video Game : {}", videoGame);
    }
 }

The important parts are :

• the @EnableWeld placed on the JUnit test class.
• the @WeldSetup placed on a WeldInitiator field, to lookup to all annotated classes.
• don't forget beans.xml in META-INF of your test classpath in order to setup the discovery-mode.
• @Slf4j is a lombok annotation, you don't need it (unless you are already using Lombok)

Here the VideoGameRepository instance benefits injection as well, like in a classical CDI project.

Here is the code of the VideoGameFactory which gets a brand new instance of the entity class marked with @Dependent scope. This factory programmatically invokes the CDI current context.

public class VideoGameFactory
{
    public static VideoGame newInstance()
    {
        // ask CDI for the instance, injecting required dependencies.
        return CDI.current().select(VideoGame.class).get();
    }
}

Alternately, you can have a look to Arquillian which can come with a full Java EE server in order to have all the needed dependencies.