props.setProperty(FessEnv.MAIL_SMTP_SERVER_MAIN_HOST_AND_PORT, "smtp-relay.example.com:465");
                props.setProperty(FessEnv.MAIL_SUBJECT_TEST_PREFIX, "[テスト環境]");
                props.setProperty(FessEnv.MAIL_RETURN_PATH, "******@****.***");
                return props;
            }
        };

        assertEquals("smtp-relay.example.com:465", specialMailEnv.getMailSmtpServerMainHostAndPort());

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

    // Test with different hostnames
    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() {