}

    @Test
    @DisplayName("computeResponse: HMAC(server||clientData) prepended to clientData")
    void testComputeResponse_basic() {
        // Arrange
        byte[] key = hex("0102030405060708090A0B0C0D0E0F10");
        byte[] serverChallenge = hex("1122334455667788");
        byte[] clientData = hex("A0A1A2A3A4");

        // Act

        String result = digest.toString();

        assertNotNull(result);
        assertTrue(result.startsWith("MacSigningKey="));
        assertTrue(result.contains("0102030405060708090A0B0C0D0E0F10"));
    }

    @Test
    @DisplayName("Test writeUTime with zero time")
    void testWriteUTimeWithZeroTime() {
        byte[] dst = new byte[4];