### Question:
ToOneFlattenedIterator implements Iterator<T> { @Override public boolean hasNext() { return next != null; } ToOneFlattenedIterator(Iterator<? extends DataObject> parentIt, String property); @Override boolean hasNext(); @Override T next();  }### Answer:
@Test public void testIterator_Empty() { List<E3> e3s = Collections.emptyList(); ToOneFlattenedIterator<DataObject> it = new ToOneFlattenedIterator<>(e3s.iterator(), E3.E2.getName()); assertFalse(it.hasNext()); }