Chapter 12. Testing a business process

A business process can be updated dynamically, which can cause errors, therefore testing a process business is also a part of the business process life cycle similar to any other development artifact.

The unit test for a business process ensures that the process behaves as expected in a specific use case. For example, you can test an output based on a particular input. To simplify unit testing, Red Hat Process Automation Manager includes the org.jbpm.test.JbpmJUnitBaseTestCase class.

The JbpmJUnitBaseTestCase performs as a base test case class, which is used for Red Hat Process Automation Manager related tests. The JbpmJUnitBaseTestCase provides the following usage areas:

The following example contains a start event, a script task, and an end event. The example JUnit test creates a new session, starts the hello.bpmn process, and verifies whether the process instance is completed and the StartProcess, Hello, and EndProcess nodes are executed.

Figure 12.1. Example JUnit Test of hello.bpmn Process

public class ProcessPersistenceTest extends JbpmJUnitBaseTestCase {

    public ProcessPersistenceTest() {
        super(true, true);
    }

    @Test
    public void testProcess() {

        createRuntimeManager("hello.bpmn");

        RuntimeEngine runtimeEngine = getRuntimeEngine();

        KieSession ksession = runtimeEngine.getKieSession();

        ProcessInstance processInstance = ksession.startProcess("com.sample.bpmn.hello");

        assertProcessInstanceNotActive(processInstance.getId(), ksession);

        assertNodeTriggered(processInstance.getId(), "StartProcess", "Hello", "EndProcess");
    }
}

JbpmJUnitBaseTestCase supports all predefined RuntimeManager strategies as part of the unit testing. Therefore, it is enough to specify the strategy that is used when you create a RuntimeManager as part of a single test. The following example shows the use of the PerProcessInstance strategy in a task service to manage user tasks:

public class ProcessHumanTaskTest extends JbpmJUnitBaseTestCase {

    private static final Logger logger = LoggerFactory.getLogger(ProcessHumanTaskTest.class);

    public ProcessHumanTaskTest() {
        super(true, false);
    }

    @Test
    public void testProcessProcessInstanceStrategy() {
        RuntimeManager manager = createRuntimeManager(Strategy.PROCESS_INSTANCE, "manager", "humantask.bpmn");
        RuntimeEngine runtimeEngine = getRuntimeEngine(ProcessInstanceIdContext.get());
        KieSession ksession = runtimeEngine.getKieSession();
        TaskService taskService = runtimeEngine.getTaskService();

        int ksessionID = ksession.getId();
        ProcessInstance processInstance = ksession.startProcess("com.sample.bpmn.hello");

        assertProcessInstanceActive(processInstance.getId(), ksession);
        assertNodeTriggered(processInstance.getId(), "Start", "Task 1");

        manager.disposeRuntimeEngine(runtimeEngine);
        runtimeEngine = getRuntimeEngine(ProcessInstanceIdContext.get(processInstance.getId()));

        ksession = runtimeEngine.getKieSession();
        taskService = runtimeEngine.getTaskService();

        assertEquals(ksessionID, ksession.getId());

        // let John execute Task 1
        List<TaskSummary> list = taskService.getTasksAssignedAsPotentialOwner("john", "en-UK");
        TaskSummary task = list.get(0);
        logger.info("John is executing task {}", task.getName());
        taskService.start(task.getId(), "john");
        taskService.complete(task.getId(), "john", null);

        assertNodeTriggered(processInstance.getId(), "Task 2");

        // let Mary execute Task 2
        list = taskService.getTasksAssignedAsPotentialOwner("mary", "en-UK");
        task = list.get(0);
        logger.info("Mary is executing task {}", task.getName());
        taskService.start(task.getId(), "mary");
        taskService.complete(task.getId(), "mary", null);

        assertNodeTriggered(processInstance.getId(), "End");
        assertProcessInstanceNotActive(processInstance.getId(), ksession);
    }
}

12.1. Testing integration with external services

Business processes often include the invocation of external services. Unit testing of a business process enables you to register test handlers that verify whether the specific services are requested correctly, and also provide test responses for the requested services.

To test the interaction with external services, use the default TestWorkItemHandler handler. You can register the TestWorkItemHandler to collect all the work items of a particular type. Also, TestWorkItemHandler contains data related to a task. A work item represents one unit of work, such as sending a specific email or invoking a specific service. The TestWorkItemHandler verifies whether a specific work item is requested during an execution of a process, and the associated data is correct.

The following example shows how to verify an email task and whether an exception is raised if the email is not sent. The unit test uses a test handler that is executed when an email is requested and enables you to test the data related to the email, such as the sender and recipient. Once the abortWorkItem() method notifies the engine about the email delivery failure, the unit test verifies that the process handles such case by generating an error and logging the action. In this case, the process instance is eventually aborted.

Figure 12.2. Example email process

public void testProcess2() {

    createRuntimeManager("sample-process.bpmn");

    RuntimeEngine runtimeEngine = getRuntimeEngine();

    KieSession ksession = runtimeEngine.getKieSession();

    TestWorkItemHandler testHandler = getTestWorkItemHandler();

    ksession.getWorkItemManager().registerWorkItemHandler("Email", testHandler);

    ProcessInstance processInstance = ksession.startProcess("com.sample.bpmn.hello2");

    assertProcessInstanceActive(processInstance.getId(), ksession);
    assertNodeTriggered(processInstance.getId(), "StartProcess", "Email");

    WorkItem workItem = testHandler.getWorkItem();
    assertNotNull(workItem);
    assertEquals("Email", workItem.getName());
    assertEquals("me@mail.com", workItem.getParameter("From"));
    assertEquals("you@mail.com", workItem.getParameter("To"));

    ksession.getWorkItemManager().abortWorkItem(workItem.getId());
    assertProcessInstanceNotActive(processInstance.getId(), ksession);
    assertNodeTriggered(processInstance.getId(), "Gateway", "Failed", "Error");

}