assertNull(block.andx, "andx should be cleared when offset is 0");
    }

    @Test
    @DisplayName("decode throws when andx command present but no andx object supplied")
    void testDecodeWithAndxCommandButNoObject() {
        DummyAndXBlock block = new DummyAndXBlock() {
            @Override
            int readHeaderWireFormat(byte[] buffer, int bufferIndex) {
                return 33;
            }