mockedCrypto.when(Crypto::getMD5).thenReturn(mockMd5);
            when(mockMd5.getDigestLength()).thenReturn(16); // MD5 digest length is 16
            HMACT64 hmac = new HMACT64(TEST_KEY);
            assertEquals(16, hmac.engineGetDigestLength());
            verify(mockMd5, times(1)).getDigestLength();
        }
    }

    @Test
    void testEngineDigest() throws NoSuchAlgorithmException {