http://elblogdepicodev.blogspot.com.es/2012/09/procesos-de-negocio-con-activiti.html

gistfile1.sh

$ $ANT_HOME/bin/ant demo.start

HelloWorld.bpmn20.xml

<definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:activiti="http://activiti.org/bpmn" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.omg.org/spec/BPMN/20100524/MODEL http://www.omg.org/spec/BPMN/2.0/20100501/BPMN20.xsd" targetNamespace="HelloWorldActiviti">

    <process id="helloWorld" name="Hola mundo" isExecutable="true">
        <startEvent id="start" />
        <sequenceFlow id="flow1" sourceRef="start" targetRef="saludarTask" />

        <scriptTask id="saludarTask" scriptFormat="groovy">
            <script>println('Hola Mundo desde el proceso!')</script>
        </scriptTask>
        <sequenceFlow id="flow2" sourceRef="saludarTask" targetRef="end" />

        <endEvent id="end" />
    </process>
</definitions>

HelloWorld.java

package es.com.blogspot.elblogdepicodev.activiti;

import org.activiti.engine.ProcessEngine;
import org.activiti.engine.ProcessEngineConfiguration;
import org.activiti.engine.ProcessEngines;
import org.activiti.engine.RepositoryService;
import org.activiti.engine.RuntimeService;
import org.h2.tools.Server;

public class HelloWorld {

	public static void main(String[] args) throws Exception {
		Server server = null;
		try {
			server = Server.createTcpServer().start();

			ProcessEngines.init();

			ProcessEngine processEngine = ProcessEngineConfiguration.createProcessEngineConfigurationFromResource("activiti-mysql.cfg.xml").buildProcessEngine();

			RuntimeService runtimeService = processEngine.getRuntimeService();
			RepositoryService repositoryService = processEngine.getRepositoryService();

			repositoryService.createDeployment().addClasspathResource("bpmn/HelloWorld.bpmn20.xml").deploy();

			runtimeService.startProcessInstanceByKey("helloWorld");
		} finally {
			ProcessEngines.destroy();
			if (server != null)
				server.stop();
		}
	}
}

HelloWorldTest.java

package es.com.blogspot.elblogdepicodev.activiti;

import org.activiti.engine.test.ActivitiRule;
import org.activiti.engine.test.Deployment;
import org.junit.Rule;
import org.junit.Test;

public class HelloWorldTest extends ActivitiAbstractTest {

	@Rule
	public ActivitiRule activitiRule = new ActivitiRule("activiti-h2.cfg.xml");

	@Test
	@Deployment(resources = "bpmn/HelloWorld.bpmn20.xml")
	public void test1() {
		activitiRule.getRuntimeService().startProcessInstanceByKey("helloWorld");

		System.out.println("Hola Mundo desde el test!");
	}
}