To run the unit tests:
$ mvn -Ptests test
Generating reports from unit tests:
$ mvn install site
Running tests individually
$ mvn -Ptests -DfailIfNoTests=false -Dtest=<test-name> test
where <test-name> is the name of the Test class without its package name
The broker is comprised of POJOs so it's simple to configure and run a broker instance and test particular functionality. Even complex test-cases involving multiple clustered brokers are relatively easy to write. Almost every test in the test-suite follows this pattern - configure broker, start broker, test functionality, stop broker.
The test-suite uses JUnit to manage test execution and life-cycle. Most tests extend org.apache.activemq.artemis.tests.util.ActiveMQTestBase which contains JUnit setup and tear-down methods as well as a wealth of utility functions to configure, start, manage, and stop brokers as well as perform other common tasks.
Check out org.apache.activemq.artemis.tests.integration.SimpleTest. It's a very simple test-case that extends org.apache.activemq.artemis.tests.util.ActiveMQTestBase and uses its methods to configure a server, run a test, and then super.tearDown() cleans it up once the test completes. The test-case includes comments to explain everything. As the name implies, this is a simple test-case that demonstrates the most basic functionality of the test-suite. A simple test like this takes less than a second to run on modern hardware.
Although org.apache.activemq.artemis.tests.integration.SimpleTest is simple it could be simpler still by extending org.apache.activemq.artemis.tests.util.SingleServerTestBase. This class does all the setup of a simple server automatically and provides the test-case with a ServerLocator, ClientSessionFactory, and ClientSession instance. org.apache.activemq.artemis.tests.integration.SingleServerSimpleTest is an example based on org.apache.activemq.artemis.tests.integration.SimpleTest but extends org.apache.activemq.artemis.tests.util.SingleServerTestBase which eliminates all the setup and class variables which are provided by SingleServerTestBase itself.
An important task for any test-case is to clean up all the resources it creates when it runs. This includes the server instance itself and any resources created to connect to it (e.g. instances of ServerLocator, ClientSessionFactory, ClientSession, etc.). This task is typically completed in the test's tearDown() method. However, ActiveMQTestBase (and other classes which extend it) simplifies this process. As org.apache.activemq.artemis.tests.integration.SimpleTest demonstrates, there are several methods you can use when creating your test which will ensure proper clean up automatically when the test is torn down. These include:
org.apache.activemq.artemis.tests.util.ActiveMQTestBase.createServer(..) methods. If you choose not to use one of these methods to create your ActiveMQServer instance then use the addServer(ActiveMQServer) method to add the instance to the test-suite's internal resource ledger.org.apache.activemq.artemis.tests.util.ActiveMQTestBase to create a ServerLocator like createInVMNonHALocator and createNettyNonHALocator. If you choose not to use one of these methods then use addServerLocator(ServerLocator) to add the locator to the test-suite's internal resource ledger.org.apache.activemq.artemis.tests.util.ActiveMQTestBase.createSessionFactory(ServerLocator) for creating your session factory. If you choose not to use this method then use org.apache.activemq.artemis.tests.util.ActiveMQTestBase.addSessionFactory to add the factory to the test-suite's internal resource ledger.There are numerous methods in org.apache.activemq.artemis.tests.util.ActiveMQTestBase to create a configuration. These methods are named like create*Config(..). Each one creates a slightly different configuration but there is a lot of overlap between them.
In any case, org.apache.activemq.artemis.core.config.Configuration is a fluent interface so it's easy to customize however you need.
If you need ideas on how to configure something or test something try looking through the test-suite at other test-cases which may be similar. This is one of the best ways to learn how the test-suite works and how you can leverage the testing infrastructure to test your particular case.