public String getHostname() {
                return "test-hostname";
            }
        };

        FessConfig fessConfig = createTestFessConfig();

        NotificationHelper notificationHelper = new NotificationHelper() {
            // Mock send method
            public void send(final Object postcard) {
                // Mock implementation
            }
        };

        notificationHelper = new NotificationHelper() {
            @Override
            public void send(CardView cardView, SMailPostingDiscloser discloser) {
                // Mock implementation
            }
        };
        ComponentUtil.register(notificationHelper, "notificationHelper");

        postbox = new Postbox() {
            // Mock implementation

import org.junit.jupiter.api.TestInfo;

public class NotificationHelperTest extends UnitFessTestCase {

    private NotificationHelper notificationHelper;

    @Override
    protected void setUp(TestInfo testInfo) throws Exception {
        super.setUp(testInfo);
        notificationHelper = new NotificationHelper();
    }

    @Test
    public void test_sendToSlack_withBlankWebhookUrls() {

import org.codelibs.fess.helper.LanguageHelper;
import org.codelibs.fess.helper.LogNotificationHelper;
import org.codelibs.fess.helper.MarkdownRenderer;
import org.codelibs.fess.helper.NotificationHelper;
import org.codelibs.fess.helper.PathMappingHelper;
import org.codelibs.fess.helper.PermissionHelper;
import org.codelibs.fess.helper.PluginHelper;
import org.codelibs.fess.helper.PopularWordHelper;

                } else {
                    toAddresses = StringUtil.EMPTY_STRINGS;
                }
                final NotificationHelper notificationHelper = ComponentUtil.getNotificationHelper();
                SMailCallbackContext.setPreparedMessageHookOnThread(notificationHelper::send);
                CrawlerPostcard.droppedInto(postbox, postcard -> {

        assertEquals(0, events.size());
    }

    @Test
    public void test_append_excludedLogger_notificationHelper() {
        final LogEvent event = createLogEvent(Level.ERROR, "org.codelibs.fess.helper.NotificationHelper", "should be excluded");
        appender.append(event);

        final List<LogNotificationEvent> events = ComponentUtil.getLogNotificationHelper().drainAll();
        assertEquals(0, events.size());
    }