How To Unit Test JMS Code

 FAQ > JMS > How To Unit Test JMS Code

When unit testing code with JMS you’ll typically want to avoid the overhead of running separate proceses; plus you’ll want to increase startup time as fast as possible as you tend to run unit tests often and want immediate feedback. Also persistence can often cause problems - as previous test case results can adversely affect future test case runs - so you often need to purge queues on startup.

So when unit testing JMS code we recommend the following

• Use an embedded broker to avoid a separate broker process being required.
• Disable broker persistence so that no queue purging is required before/after tests.
• It’s often simpler and faster to just use Java code to create the broker via an XML configuration file using Spring etc.

You can do all of this using the following Java code to create your JMS ConnectionFactory which will also automatically create an embedded broker

ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("vm://localhost?broker.persistent=false");

For more configuration options see the VM Transport Reference and the Broker Configuration URI

Or if you really would rather be more explicit you can create the broker first using the following Java code

BrokerService broker = new BrokerService();
broker.setPersistent(false);
broker.start();

or you could use Spring Support.

Using JNDI

If your application code is using JNDI to lookup the JMS ConnectionFactory and Destination’s to use, then you could use the JNDI Support in ActiveMQ Classic.

Add the following jndi.properties to your classpath, e.g., in src/test/resources, if you are using maven:

java.naming.factory.initial = org.apache.activemq.jndi.ActiveMQInitialContextFactory
java.naming.provider.url = vm://localhost?broker.persistent=false

You should then consider using Dynamic destinations in JNDI so that your code looks up destinations via

context.lookup("dynamicQueues/FOO.BAR");

Using The EmbeddedActiveMQBroker JUnit Rule (ActiveMQ 5.13)

If your test code is using JUnit, then you could use the EmbeddedActiveMQBroker JUnit Rule provided in the activemq-junit library. Add the activemq-junit library along with the activemq-broker libraries for the version of ActiveMQ Classic you want to test with.  The rule will use whatever version of ActiveMQ Classic it finds in the classpath, so the ActiveMQ Classic libraries need to be specified if they are not already there.

If you are using Maven, add the following to your pom.xml:

<dependency>
    <groupId>org.apache.activemq.tooling</groupId>
    <artifactId>activemq-junit</artifactId>
    <version>${activemq-junit-version}</version>
    <scope>test</scope>
</dependency> 

<dependency>
    <groupId>org.apache.activemq</groupId>
    <artifactId>activemq-broker</artifactId>
    <version>${activemq-version}</version>
    <scope>test</scope>
</dependency>

 Then add the EmbeddedActiveMQBroker JUnit Rule to your test, and JUnit will start the embedded broker at the beginning of each test and stop the broker at the end of the test.

Use The ActiveMQ Classic JUnit Rule

@Rule
public EmbeddedActiveMQBroker broker = new EmbeddedActiveMQBroker();

By default, the EmbeddedActiveMQBroker will configure the broker as non-persistent, and the only transport available will be the VM transport. To customize this configuration, either extend the EmbeddedActiveMQBroker class and override the configure() method, or use an XML configuration for the broker.  

Note: to configure an EmbeddedActiveMQBroker using XML configuration, you may need to add additional libraries to the classpath to support XBean configuration of ActiveMQ.

Customizing An EmbeddedActiveMQBroker Using Java

@Rule
EmbeddedActiveMQBroker customizedBroker = new EmbeddedActiveMQBroker() {
    @Override
    protected void configure() {
        // Perform additional configuration here...
    }
}

Customizing An EmbeddedActiveMQBroker Using XML Configuration

@Rule
EmbeddedActiveMQBroker customizedBroker = new EmbeddedActiveMQBroker("bean:customize-activemq.xml");

Note that to use the XML configuration, you may need to add additional libraries on the classpath to support the XBean configuration of ActiveMQ Classic.  The versions of the spring-context library should correspond with the version used by your selected version of ActiveMQ Classic.

Maven Configuration For XBean Configuration

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>Appropriate version for activemq-version</version>
</dependency>

<dependency>
    <groupId>org.apache.activemq</groupId>
    <artifactId>activemq-spring</artifactId>
    <version>${activemq-version></version>
</dependency>

Then you can use the VM URI to connect with the broker

ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("vm://embedded-broker?create=false");

You can also get a connection factory from the EmbeddedActiveMQBroker:

ConnectionFactory connectionFactory = embeddedBroker.createConnectionFactory();