}
    }

    // Test with different hostnames
    @Test
    public void test_differentHostnames() {
        String[] hostnames = { "smtp.gmail.com", "mail.example.com", "localhost", "192.168.1.1" };

        for (String hostname : hostnames) {
            ComponentUtil.setFessConfig(new FessConfig.SimpleImpl() {

        // IPv4 addresses - should remain unchanged
        assertEquals("127.0.0.1", IpAddressUtil.formatForUrl("127.0.0.1"));
        assertEquals("192.168.1.1", IpAddressUtil.formatForUrl("192.168.1.1"));

        // Hostnames - should remain unchanged
        assertEquals("localhost", IpAddressUtil.formatForUrl("localhost"));
        assertEquals("example.com", IpAddressUtil.formatForUrl("example.com"));

        // Null

                // State has changed
                return true;
            }

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

        FessConfig fessConfig = createTestFessConfig();

        // Register components
        ComponentUtil.register(searchEngineClient, "searchEngineClient");

    }

    /**
     * Set the value of hostname, used in parameter comment. <br>
     * Even if empty string, treated as empty plainly. So "IF pmb != null" is false if empty.
     * @param hostname The parameter value of hostname. (NotNull)
     */
    public void setHostname(String hostname) {
        registerVariable("hostname", hostname);
    }

    /**

        final String hostname = ComponentUtil.getSystemHelper().getHostname();
        final String targetName = ComponentUtil.getFessConfig().getSchedulerTargetName();

        final String body = toJson(Map.of( //
                "type", TYPE_HEARTBEAT, //
                "instanceId", instanceId, //
                "hostname", hostname, //

                                    <label for="hostname" class="col-sm-3 text-sm-right col-form-label"><la:message
                                            key="labels.file_auth_hostname"/></label>
                                    <div class="col-sm-9">
                                        <la:errors property="hostname"/>
                                        <la:text styleId="hostname" property="hostname" styleClass="form-control"/>

                                    <label for="hostname" class="col-sm-3 text-sm-right col-form-label"><la:message
                                            key="labels.webauth_hostname"/></label>
                                    <div class="col-sm-9">
                                        <la:errors property="hostname"/>
                                        <la:text styleId="hostname" property="hostname" styleClass="form-control"/>

                                                                test="${data.hostname==null||data.hostname==''}">
                                                            <la:message key="labels.webauth_any"/>
                                                        </c:if> ${f:h(data.hostname)}: <c:if
                                                                test="${data.port==null||data.port==''}">

    }

    /**
     * Gets host information including hostname and IP address.
     *
     * @return formatted string containing hostname and IP address
     */
    protected String getHostInfo() {
        final StringBuilder buf = new StringBuilder();
        try {
            final InetAddress ia = InetAddress.getLocalHost();
            final String hostname = ia.getHostName();

                for (final LogNotificationEvent event : batch) {
                    final Map<String, Object> source = new HashMap<>();
                    source.put("hostname", hostname);
                    source.put("level", event.getLevel());
                    source.put("loggerName", event.getLoggerName());
                    source.put("message", event.getMessage());