assertEquals("********", SystemUtil.maskSensitiveValue("private_config", "internal"));
    }

    @Test
    public void test_maskSensitiveValue_safeValues() {
        // These should NOT be masked
        assertEquals("localhost:9200", SystemUtil.maskSensitiveValue("HOST", "localhost:9200"));
        assertEquals("8080", SystemUtil.maskSensitiveValue("PORT", "8080"));