### Question:
MapBackedSet extends AbstractSet<E> implements Serializable { @Override public int size() { return map.size(); } MapBackedSet(Map<E, Boolean> map); @Override int size(); @Override boolean contains(Object o); @Override boolean add(E o); @Override boolean remove(Object o); @Override void clear(); @Override Iterator<E> iterator();  }### Answer:
@Test @SuppressWarnings({ "unchecked", "rawtypes" }) public void testSize() { Map map = createStrictMock(Map.class); expect(map.size()).andReturn(0); replay(map); assertEquals(0, new MapBackedSet(map).size()); verify(map); }