What is the best way to unit test a EJB3 component without having to deploy the component.

Question

I would like to have a JUnit (or other) system where the enterprise beans can be tested in a mock environment so that all resources/beans and so on are injected locally. The enterprise beans should not have to accomplish this. All kinds of injection should be supported.

• I would like to have a maven plugin for this so that the tests can be run from a maven build.
• Transactions are not necessary during the unit tests,this would require a complete container.

Do you know of such a maven plugin or test framework? Experiences with it?

Answer 1

Not necessarily the easiest way, but I managed to get this working using JBoss's embeddable EJB3.0 container, with major assistance from Java Persistence with Hibernate

For a start, I don't know of maven plugins/dependencies for this, so I had to install my own locally:

(1) Download jboss-EJB-3.0_Embeddable_ALPHA_9.zip from downloads

(2) This zipfile contains two important JARs:

• jboss-ejb3-all.jar
• thirdparty-all.jar

(3) Install these JARs into your local repository (use your own initials instead of nkl):

mvn install:install-file \
    -Dfile=jboss-ejb3-all.jar \
    -DgroupId=nkl.jboss.embedded \
    -DartifactId=jboss-ejb3-all \
    -Dversion=3.0-alpha-9

mvn install:install-file \
    -Dfile=thirdparty-all.jar \
    -DgroupId=nkl.jboss.embedded \
    -DartifactId=thirdparty-all \
    -Dversion=3.0-alpha-9

(4) If all has gone well, you should now have two directories in your local repository.

(5) Now add the following dependencies to your pom.xml

    <dependency>
      <groupId>nkl.jboss.embedded</groupId>
      <artifactId>jboss-ejb3-all</artifactId>
      <version>3.0-alpha-9</version>
    </dependency>
    <dependency>
      <groupId>nkl.jboss.embedded</groupId>
      <artifactId>thirdparty-all</artifactId>
      <version>3.0-alpha-9</version>
    </dependency>

(6) I also needed to add dependencies for HSQLDB, and SLF4J

(7) You need to copy some files from the conf directory of the zipfile to the src/main/resources directory of your project:

• default.persistence.properties
• ejb3-interceptors-aop.xml
• embedded-jboss-beans.xml
• jndi.properties

(8) I created my own beans.xml and persistence.xml files in src/main/resources/META-INF:

<?xml version="1.0" encoding="UTF-8"?>
<deployment xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="urn:jboss:bean-deployer bean-deployer_1_0.xsd" xmlns="urn:jboss:bean-deployer">
  <bean name="messageDSBootstrap" class="org.jboss.resource.adapter.jdbc.local.LocalTxDataSource">
    <property name="jndiName">java:/messageDS</property>
    <property name="driverClass">org.hsqldb.jdbcDriver
    </property>
    <property name="connectionURL">jdbc:hsqldb:test</property>
    <property name="minSize">0</property>
    <property name="maxSize">10</property>
    <property name="blockingTimeout">1000</property>
    <property name="idleTimeout">30000</property>
    <property name="transactionManager">
      <inject bean="TransactionManager" />
    </property>
    <property name="cachedConnectionManager">
      <inject bean="CachedConnectionManager" />
    </property>
    <property name="initialContextProperties">
      <inject bean="InitialContextProperties" />
    </property>
  </bean>
  <bean name="messageDS" class="java.lang.Object">
    <constructor factoryMethod="getDatasource">
      <factory bean="messageDSBootstrap" />
    </constructor>
  </bean>
</deployment>

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/persistence 
  http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
  version="1.0">
  <persistence-unit name="jpa">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <jta-data-source>java:/messageDS</jta-data-source>
    <properties>
      <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect" />
      <property name="hibernate.show_sql" value="true" />
      <property name="hibernate.format_sql" value="true" />
      <property name="hibernate.hbm2ddl.auto" value="create" />
    </properties>
  </persistence-unit>
</persistence>

(9) I created a unit test like the following, using additional infomation from here.

package org.nkl;

import java.io.File;

import javax.naming.InitialContext;

import org.jboss.ejb3.embedded.EJB3StandaloneBootstrap;
import org.jboss.ejb3.embedded.EJB3StandaloneDeployer;
import org.junit.Test;
import org.nkl.model.MessageHandler;

public class BasicTest {

    @Test
    public void testEjb() throws Exception {
        EJB3StandaloneBootstrap.boot(null);
        EJB3StandaloneBootstrap.deployXmlResource("META-INF/beans.xml");
        EJB3StandaloneDeployer deployer = EJB3StandaloneBootstrap
                .createDeployer();

        deployer.getArchives().add(new File("target/classes").toURI().toURL());

        deployer.create();
        deployer.start();
        InitialContext context = new InitialContext();
        MessageHandler messageHandler = (MessageHandler) context
                .lookup("MessageHandlerBean/local");
        messageHandler.saveMessages();
        messageHandler.showMessages();
        EJB3StandaloneBootstrap.shutdown();
    }
}

(10) This uses a simple SLSB like:

package org.nkl.ejb;

import java.util.List;

import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import org.nkl.model.Message;
import org.nkl.model.MessageHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Stateless
public class MessageHandlerBean implements MessageHandler {

    @PersistenceContext
    private EntityManager em;

    Logger logger = LoggerFactory.getLogger(MessageHandlerBean.class);

    public void saveMessages() {
        logger.info("In saveMessages");
        em.persist(new Message("Hello World"));
    }

    @SuppressWarnings("unchecked")
    public void showMessages() {
        logger.info("In showMessages");
        List messages = em.createQuery(
                "select m from Message m order by m.text asc").getResultList();
        for (Object o : messages) {
            logger.info(((Message) o).getText());
        }
    }
}

(11) And a Message entity class like:

package org.nkl.model;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
@Table(name = "MESSAGES")
public class Message {
    @Id
    @GeneratedValue
    @Column(name = "MESSAGE_ID")
    private Long id;
    @Column(name = "MESSAGE_TEXT")
    private String text;
    @ManyToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "NEXT_MESSAGE")
    private Message nextMessage;

    public Message(String text) {
        this.text = text;
    }

    Message() {}

    // setters/getters not shown.

}

---

Lets just say there are a number of stumbling blocks along the way in this approach.

Notably to do with the order of dependencies.

Good luck!!

Answer 2

I must warn that JBoss embedded is a mess. You don't need to believe my word. See the forums for yourself. It is alpha by all possible means. Things may work for you now but who knows what bugs are still waiting there... Assuming that your project will live for a long time.. that's a risk.

You can try OpenEJB. It is limited in some aspects (in terms of flexibility) but it is really easy to use and full compliant with the spec. There are a few links such as this and this. Download it and give it a try. By the way, OpenEJB came to my attention by reading JBoss Embedded Forum posts... from angry users pointing alternatives.

Personally, I decided to create for my projects a kind of mock container that allows me to test almost anything I need. For persistence I use Hibernate Entity Manager + HSQL. It took me a week to implement but my teams (2 so far) are very happy with it. I'll make it open-source if possible.

The last option is ejb3unit.