hmac.engineReset();
        // After reset, should be able to digest again
        byte[] result = hmac.engineDigest();
        assertNotNull(result);
    }

    @Test
    void testEngineGetDigestLength() {
        // Test engineGetDigestLength()
        HMACT64 hmac = new HMACT64(TEST_KEY);
        // MD5 digest length is 16 bytes
        assertEquals(16, hmac.engineGetDigestLength());
    }

    @Test