private static final long serialVersionUID = 1L;

                @Override
                public String getMailFromAddress() {
                    return from;
                }
            });

            assertEquals(from, ComponentUtil.getFessConfig().getMailFromAddress());
        }
    }

    // Test with different hostnames
    public void test_differentHostnames() {

                    SMailCallbackContext.setPreparedMessageHookOnThread(notificationHelper::send);
                    EsStatusPostcard.droppedInto(postbox, postcard -> {
                        postcard.setFrom(fessConfig.getMailFromAddress(), fessConfig.getMailFromName());
                        postcard.addReplyTo(fessConfig.getMailReturnPath());
                        if (toAddresses.length > 0) {

                SMailCallbackContext.setPreparedMessageHookOnThread(notificationHelper::send);
                CrawlerPostcard.droppedInto(postbox, postcard -> {
                    postcard.setFrom(fessConfig.getMailFromAddress(), fessConfig.getMailFromName());
                    postcard.addReplyTo(fessConfig.getMailReturnPath());
                    if (toAddresses.length > 0) {

        final Postbox postbox = ComponentUtil.getComponent(Postbox.class);
        try {
            TestmailPostcard.droppedInto(postbox, postcard -> {
                postcard.setFrom(fessConfig.getMailFromAddress(), fessConfig.getMailFromName());
                postcard.addReplyTo(fessConfig.getMailReturnPath());
                stream(toAddresses).of(stream -> stream.forEach(address -> {
                    postcard.addTo(address);

            }

            @Override
            public String getNotificationTo() {
                return "******@****.***";
            }

            @Override
            public String getMailFromAddress() {
                return "******@****.***";
            }

            @Override
            public String getMailFromName() {
                return "Fess Crawler";
            }

        }

        @Override
        public String getNotificationTo() {
            return "******@****.***,******@****.***";
        }

        @Override
        public String getMailFromAddress() {
            return "******@****.***";
        }

        @Override
        public String getMailFromName() {
            return "Fess System";
        }

        @Override

     * comment: Email address to use in the From field.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getMailFromAddress();

    /**
     * Get the value for the key 'mail.hostname'. <br>
     * The value is, e.g.  <br>
     * comment: Hostname for the mail server.