assertEquals(len, digest.lastLength);
    }

    @Test
    @DisplayName("writeAndXWireFormat without andx writes 0xFF and sentinel offset")
    void testWriteAndXWireFormatWithoutAndx() {
        DummyAndXBlock block = new DummyAndXBlock();
        byte[] buf = new byte[128];
        int n = block.writeAndXWireFormat(buf, 0);

        assertTrue(n > 0);