assertEquals("********", SystemUtil.maskSensitiveValue("REFRESH_TOKEN", "1//0eXyz"));
    }

    @Test
    public void test_maskSensitiveValue_withCredential() {
        assertEquals("********", SystemUtil.maskSensitiveValue("GOOGLE_CREDENTIALS", "{}"));
        assertEquals("********", SystemUtil.maskSensitiveValue("credential", "user:pass"));
    }