How To Create Junit 4 Tests With Weld

Programming

Challenge

You want to write a couple of Integration tests with JUnit and want to use Weld for the CDI part, but don’t know how…


Solution

Add Weld dependency to your maven project

Weld dependency

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<dependency>
    <groupId>org.jboss.weld.se</groupId>
    <artifactId>weld-se</artifactId>
    <version>2.3.3.Final</version>
    <scope>test</scope>
</dependency>

Create a couple of helper classes:

WeldContext

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packkage nl.ivonet.helper;
import org.jboss.weld.environment.se.Weld;
import org.jboss.weld.environment.se.WeldContainer;

public class WeldContext {
    private final WeldContainer weldContainer;

    private WeldContext() {
        final Weld weld = new Weld();
        this.weldContainer = weld.initialize();
    }


    public static WeldContext getInstance() {
        return WeldContext.Instance.SINGLETON;
    }

    private static final class Instance {
        static final WeldContext SINGLETON = new WeldContext();
    }

    public <T> T getBean(final Class<T> type) {
        return this.weldContainer.instance()
                                 .select(type)
                                 .get();
    }
}

WeldJUnit4Runner

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package nl.ivonet.helper;

import org.junit.runners.BlockJUnit4ClassRunner;
import org.junit.runners.model.InitializationError;

public class WeldJUnit4Runner extends BlockJUnit4ClassRunner {

    public WeldJUnit4Runner(final Class<Object> clazz) throws InitializationError {
        super(clazz);
    }

    @Override
    protected Object createTest() {
        return WeldContext.getInstance().getBean(getTestClass().getJavaClass());
    }
}

Initialize bean context for test by creating in the src/test/resources/META-INF folder the beans.xml file

beans.xml

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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
                           http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd"
       bean-discovery-mode="all">
</beans>

Now write your test:

JUnit test

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import nl.ivonet.helper.WeldJUnit4Runner;
import org.junit.Test;
import org.junit.runner.RunWith;
import javax.inject.Inject;
import static org.junit.Assert.assertNotNull;

@RunWith(WeldJUnit4Runner.class) //The one you created
public class FooTest {

    @Inject
    private Foo foo; //just an example class to inject

    @Test
    public void testNotNull() throws Exception {
       //meaningless test but enough to illustrate the workings...
       assertNotNull(foo); 
    }
}
  • Run your tests and you should see it working…