### Question:
ObservableListDecorator extends AbstractList<T> { void setAll(Collection<? extends T> elements) { delegate.setAll(elements); }  @Override T get(int index); @Override int size();  }### Answer:
@Test public void testSetAll() { ObservableListDecorator<Integer> list = new ObservableListDecorator<>(); Collection<Integer> state = Lists.newArrayList(3, 2, 1); list.setAll(state); assertEquals(state, list); state = Lists.newArrayList(0, 0, 0, 0); list.setAll(state); assertEquals(state, list); }