How to Test UI Event Publishing in Jmix

Community Solutions and Guides
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How to Test UI Event Publishing in Jmix – A Community Solution

Recently, a question came up on Slack about how to test if specific UI events are published in a Jmix application. To address this, I’ve built a small example demonstrating how to implement such a test.

You can find the complete example project on GitHub:

GitHub Repository: Jmix UI Integration Test Events

Why Would You Test UI Event Publishing?

In Jmix applications, custom UI events are often used to trigger or handle actions in response to user interaction. For example, you might want to log when a user opens a certain view or fire events when certain conditions are met. It’s essential to verify that these events are published correctly, especially in larger applications with complex UI workflows.

With this test setup, you can check if your custom UI events are published as expected when certain actions, such as navigating to a view, take place.

Example Overview

In the example, we perform an integration test for a custom event, UserListViewOpenedEvent, which is fired when the UserListView is opened. The test captures the published event and verifies that it has been triggered.

The key parts of this project include:

  • A production UserListView that publishes the UserListViewOpenedEvent when attached to the UI.
  • A custom TestUiEventPublisher to track and store events during the test lifecycle.
  • A Spring test configuration to replace the default UiEventPublisher with the custom test publisher.
  • An integration test that navigates to the UserListView and validates that the event is published.

Full Example

Here’s the relevant content from the project’s README.md:

Jmix Integration Test: Custom Event Publishing

This example project demonstrates how to perform integration tests in a Jmix application that involve publishing custom UI events. Specifically, it shows how to capture and validate that a custom event, UserListViewOpenedEvent, is published when a specific view (UserListView) is opened.

Overview

The project uses the Jmix framework with Spring Boot and Vaadin for UI. We extend Jmix’s UiEventPublisher to track published events during test execution. This is done using a custom test utility TestUiEventPublisher.

The project includes:

  • A production UserListView class that publishes a custom event when the view is attached.
  • A custom event publisher (TestUiEventPublisher) that records all UI events during test execution.
  • A test configuration class to register this custom publisher.
  • An integration test (UserUiTest) that verifies if the UserListViewOpenedEvent is published when the user navigates to the UserListView.

Key Classes

1. UserListView

This is the production class that defines the user list view. It uses Vaadin’s @Route to define the URL path and publishes a UserListViewOpenedEvent when the view is attached to the UI.

@Route(value = "users", layout = MainView.class)
@ViewController("User.list")
@ViewDescriptor("user-list-view.xml")
@LookupComponent("usersDataGrid")
@DialogMode(width = "64em")
public class UserListView extends StandardListView<User> {
    @Autowired
    private UiEventPublisher uiEventPublisher;

    @Subscribe
    public void onAttachEvent(final AttachEvent event) {
        uiEventPublisher.publishEventForCurrentUI(new UserListViewOpenedEvent(this));
    }
}
  • Key method: onAttachEvent(AttachEvent event) triggers when the view is attached to the UI and publishes the UserListViewOpenedEvent for the current UI.

2. TestUiEventPublisher

This class extends Jmix’s UiEventPublisher to capture all published events during testing. It overrides the publish method to store each event in a list for later verification.

public class TestUiEventPublisher extends UiEventPublisher {

    private final List<ApplicationEvent> publishedEvents = new ArrayList<>();

    public TestUiEventPublisher(SystemAuthenticator systemAuthenticator, ClusterApplicationEventPublisher clusterApplicationEventPublisher, SessionHolder sessionHolder, CurrentAuthentication currentAuthentication) {
        super(systemAuthenticator, clusterApplicationEventPublisher, sessionHolder, currentAuthentication);
    }

    public List<ApplicationEvent> getPublishedEvents() {
        return publishedEvents;
    }

    @Override
    protected void publish(Collection<UI> uis, ApplicationEvent event) {
        super.publish(uis, event);
        publishedEvents.add(event);
    }
}
  • Key method: getPublishedEvents() returns the list of events published during the test.

3. TestUiEventPublisherConfiguration

A Spring test configuration that overrides the default UiEventPublisher with TestUiEventPublisher for test purposes.

@TestConfiguration
public class TestUiEventPublisherConfiguration {

    @Bean("flowui_UiEventPublisher")
    public UiEventPublisher uiEventPublisher(SystemAuthenticator systemAuthenticator, ClusterApplicationEventPublisher clusterApplicationEventPublisher, SessionHolder sessionHolder, CurrentAuthentication currentAuthentication) {
        return new TestUiEventPublisher(systemAuthenticator, clusterApplicationEventPublisher, sessionHolder, currentAuthentication);
    }
}

4. UserUiTest

An integration test that simulates the navigation to the UserListView and verifies that the UserListViewOpenedEvent is fired.

Important Test Configuration Notes:

  1. Bean Definition Override: It’s important to set the property spring.main.allow-bean-definition-overriding=true in the test configuration. This allows your test configuration to override the standard UiEventPublisher with the TestUiEventPublisher.

  2. Test Event Publisher Configuration: Ensure that TestUiEventPublisherConfiguration is included in the test classes configuration. This replaces the default publisher with the test-specific version, allowing event tracking during tests.

  3. Inject the TestUiEventPublisher: Instead of injecting the regular UiEventPublisher, make sure to inject TestUiEventPublisher in the test class to gain access to the getPublishedEvents() method, which is crucial for validating that events have been published.

@UiTest
@SpringBootTest(
        properties = {"spring.main.allow-bean-definition-overriding=true"},
        classes = {
                JmixSampleUiIntegrationTestEventsApplication.class,
                FlowuiTestAssistConfiguration.class,
                TestUiEventPublisherConfiguration.class  // Ensure Test configuration is included
        })
public class UserUiTest {

    @Autowired
    DataManager dataManager;

    @Autowired
    ViewNavigators viewNavigators;

    @Autowired
    private TestUiEventPublisher testUiEventPublisher; // Inject the test event publisher

    @Test
    void when_openListView_then_UserListViewOpenedEventFired() {

        // when:
        viewNavigators.view(UiTestUtils.getCurrentView(), UserListView.class).navigate();

        // then:
        assertThat(testUiEventPublisher.getPublishedEvents())  // Use TestUiEventPublisher
                .hasSize(1);

        // and:
        assertThat(testUiEventPublisher.getPublishedEvents())
                .anyMatch(applicationEvent -> applicationEvent instanceof UserListViewOpenedEvent);
    }

    @AfterEach
    void tearDown() {
        dataManager.load(User.class)
                .query("e.username like ?1", "test-user-%")
                .list()
                .forEach(u -> dataManager.remove(u));
    }
}

Running the Tests

To run the integration tests, use the following command:

./gradlew test
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