@Override
    public Decoder<Object> getMapValueDecoder() {
        return mapValueDecoder;
    }
@Test
    public void shouldDeserializeTheMapCorrectly() throws Exception {
        ByteBuf buf = ByteBufAllocator.DEFAULT.buffer();
        buf.writeBytes(new ObjectMapper().writeValueAsBytes(map));
        assertThat(mapCodec.getMapValueDecoder().decode(buf, new State()))
                .isInstanceOf(Map.class)
                .isEqualTo(map);
        buf.release();
    }