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

    @Test
    public void test_append_nonExcludedLogger() {
        final LogEvent event = createLogEvent(Level.ERROR, "org.codelibs.fess.helper.SystemHelper", "not excluded");
        appender.append(event);

        final List<LogNotificationEvent> events = ComponentUtil.getLogNotificationHelper().drainAll();
        assertEquals(1, events.size());

    protected void setUp(TestInfo testInfo) throws Exception {
        super.setUp(testInfo);
        ComponentUtil.register(new LogNotificationHelper(), "logNotificationHelper");
        ComponentUtil.getLogNotificationHelper().drainAll();
        ComponentUtil.getFessConfig().setLogNotificationEnabled(true);
        logNotificationTarget = new LogNotificationTarget();
    }

    @Test
    public void test_constructor() {

        List<LogNotificationEvent> events = helper.drainAll();
        assertEquals(2, events.size());
        assertEquals("message1", events.get(0).getMessage());
        assertEquals("message2", events.get(1).getMessage());
    }

    @Test
    public void test_drainAll_empty() {
        LogNotificationHelper helper = new LogNotificationHelper();
        List<LogNotificationEvent> events = helper.drainAll();
        assertNotNull(events);

        try {
            helper = ComponentUtil.getLogNotificationHelper();
        } catch (final Exception e) {
            return;
        }

        final List<LogNotificationEvent> events = helper.drainAll();
        if (events.isEmpty()) {
            return;
        }

        try {
            final SearchEngineClient client = ComponentUtil.getSearchEngineClient();