CDI in JUnit tests with Jersey Test Framework - dependency-injection

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.