final ModelSet model = (ModelSet) JsonLdProcessor.toRDF(input, callback);
// contains only one statement (type)
final ClosableIterator<Statement> statements = model.iterator();
final Statement stmt = statements.next();
assertEquals(expectedString, stmt.getContext() + " - " + stmt.toString());
assertFalse("Deserialized RDF contains more triples than expected", statements.hasNext());
}