EntryCallback callback = new EntryCallback();
Map<String, ODataCallback> callbacks = new HashMap<String, ODataCallback>();
callbacks.put("nr_Building", callback);
final ODataResponse response =
new JsonEntityProvider().writeEntry(entitySet, roomData,
EntityProviderWriteProperties.serviceRoot(URI.create(BASE_URI)).expandSelectTree(node1)
.callbacks(callbacks).build());
assertNotNull(response);
assertNotNull(response.getEntity());
assertNull("EntitypProvider must not set content header", response.getContentHeader());