provider.setInDropElements(Collections.singletonList("Extra"));
ByteArrayInputStream is = new ByteArrayInputStream(data.getBytes());
Object o = provider.readFrom((Class)ManyTags.class, ManyTags.class,
new Annotation[0], MediaType.APPLICATION_JSON_TYPE,
new MetadataMap<String, String>(), is);
ManyTags holder = (ManyTags)o;
assertNotNull(holder);
TagVO tag = holder.getTags().getTags().get(0);
assertEquals("a", tag.getName());
assertEquals("b", tag.getGroup());
}