assertEquals("8080", SystemUtil.maskSensitiveValue("PORT", "8080"));
        assertEquals("/var/log/fess", SystemUtil.maskSensitiveValue("LOG_DIR", "/var/log/fess"));
        assertEquals("production", SystemUtil.maskSensitiveValue("ENVIRONMENT", "production"));
        assertEquals("admin", SystemUtil.maskSensitiveValue("USER_NAME", "admin"));