provider.setInAppendAttributes(map);
ByteArrayInputStream is = new ByteArrayInputStream(data.getBytes());
Object o = provider.readFrom((Class)TagVO2Holder.class, TagVO2Holder.class,
new Annotation[0], MediaType.APPLICATION_JSON_TYPE,
new MetadataMap<String, String>(), is);
TagVO2Holder holder = (TagVO2Holder)o;
assertEquals("custom", holder.getAttribute());
TagVO2 tag2 = holder.getTagValue();
assertEquals("A", tag2.getName());
assertEquals("B", tag2.getGroup());
}