How to test methods in Saga that has internal state - axon

Question

given this saga:
#Saga
#Getter
#Slf4j
public class TasksForStateSaga {
#Autowired
transient CommandGateway commandGateway;
#Autowired
transient EventBus eventBus;
#Autowired
transient TaskService taskService;
Map<String, TaskStatus> tasks = new HashMap<>();
ApplicationState applicationState;
#StartSaga
#SagaEventHandler(associationProperty = "id")
public void on(ApplicationStateChangedEvent event) {
applicationState = event.getNewState();
log.info("Planning tasks for application {} in state {}", event.getId(), applicationState);
taskService.getTasksByState(applicationState).stream()
.map(task -> ScheduleTaskCommand.builder()
.applicationId(event.getId())
.taskId(IdentifierFactory.getInstance().generateIdentifier())
.targetState(applicationState)
.taskName(task.getTaskName())
.build())
.peek(command -> tasks.put(command.getTaskId(), SCHEDULED))
.forEach(command -> commandGateway.send(command));
}
#SagaEventHandler(associationProperty = "applicationId")
public void on(TaskFinishedEvent event) {
tasks.replace(event.getTaskId(), FINISHED);
long notFinished = getUnfinishedCount();
log.info("Task {} has just finished, ready {} of {}", event.getTaskName(), tasks.size() - notFinished, tasks.size());
if (notFinished == 0) {
log.info("All tasks for application {}.{} finished, ending this saga", event.getApplicationId(), applicationState);
eventBus.publish(GenericEventMessage.asEventMessage(
TaskForStateDoneEvent.builder()
.applicationId(event.getApplicationId())
.state(applicationState)
.build()
));
SagaLifecycle.end();
}
}
private long getUnfinishedCount() {
return tasks.values().stream()
.filter(state -> !FINISHED.equals(state))
.count();
}
}
And have this test (Spock) testing the first method:
class TasksForStateSagaTest extends Specification {
SagaTestFixture sagaFixture
def setup() {
sagaFixture = new SagaTestFixture<>(TasksForStateSaga)
}
def 'should schedule task for the application state'() {
given:
def applicationId = '1'
def taskService = Mock(TaskService)
def tasks = [
ApplicationStateAwareTaskDefinition.builder().taskName('task1').build(),
ApplicationStateAwareTaskDefinition.builder().taskName('task2').build(),
]
sagaFixture.registerResource(taskService)
sagaFixture.givenAggregate(applicationId)
when:
sagaFixture
.whenPublishingA(new ApplicationStateChangedEvent(id: applicationId, newState: ApplicationState.NEW))
.expectActiveSagas(1)
.expectDispatchedCommandsMatching(payloadsMatching(
exactSequenceOf(
equalTo(new ScheduleTaskCommand(applicationId: applicationId, targetState: ApplicationState.NEW, taskName: 'task1'),
new IgnoreField(ScheduleTaskCommand, 'taskId')),
equalTo(new ScheduleTaskCommand(applicationId: applicationId, targetState: ApplicationState.NEW, taskName: 'task2'),
new IgnoreField(ScheduleTaskCommand, 'taskId')),
andNoMore()
)
))
then:
1 * taskService.getTasksByState(ApplicationState.NEW) >> tasks
}
}
But I actually have no clue how to test the second method, which uses the Saga's internal state.
Could anyone advice me how to set the internal saga's state via SagaTestFixture?
Or even more, is this the good way how to implement such saga or I have there some conceptual issues preventing me to test the end saga method easily?
the #StartSaga method sets the internal state - generates taskId and sets it into map
the #EndSaga method reads the map and checks if all tasks are done prior it sends TaskForStateDoneEvent event
thanks!

Answer 1

I have achieved this by defining callback for the saga fixture. This callbacks catches all the commands of the desired type and stores the ids temporally
def 'saga should end when all scheduled tasks finished'() {
given:
def applicationId = '1'
def taskService = Mock(TaskService)
def tasks = [
ApplicationStateAwareTaskDefinition.builder().taskName('task1').build(),
ApplicationStateAwareTaskDefinition.builder().taskName('task2').build(),
]
def scheduleTaskCommands = []
sagaFixture.registerResource(taskService)
sagaFixture.setCallbackBehavior(new CallbackBehavior() {
#Override
Object handle(Object commandPayload, MetaData commandMetaData) {
if (commandPayload instanceof ScheduleTaskCommand) {
// catch the issued commands to get the new task ids
scheduleTaskCommands << commandPayload
}
commandPayload
}
})
when:
sagaFixture
.givenAggregate(applicationId)
.published(new ApplicationStateChangedEvent(
applicationId: applicationId,
newState: ApplicationState.NEW
))
// publish event to finish first task (first from two)
sagaFixture.givenAPublished(new TaskFinishedEvent(
taskName: 'someTaskName',
applicationId: applicationId,
taskId: scheduleTaskCommands[0].taskId,
taskResult: new TaskResult(
status: TaskResultStatus.SUCCEED,
message: 'ok'
)))
// verify the behaviour after second task finished
sagaFixture
.whenPublishingA(new TaskFinishedEvent(
taskName: 'someTaskName',
applicationId: applicationId,
taskId: scheduleTaskCommands[1].taskId,
taskResult: new TaskResult(
status: TaskResultStatus.SUCCEED,
message: 'ok'
)))
.expectActiveSagas(0)
.expectPublishedEvents(new TasksForStateFinishedEvent(
applicationId: applicationId,
state: ApplicationState.NEW
))
then:
1 * taskService.getTasksByState(ApplicationState.NEW) >> tasks
}