### Question:
RedBlackTree implements Iterable<RedBlackEntry<K, V>> { public int size() { return size; } RedBlackTree(); int size(); boolean containsKey(K key); RedBlackEntry<K, V> getFirst(); RedBlackEntry<K, V> getLast(); RedBlackEntry<K, V> getEntryLessThanEqual(K key); RedBlackEntry<K, V> getEntryGreaterThanEqual(K key); V put(K key, V value); RedBlackEntry<K, V> getOrCreateEntry(K key); RedBlackEntry<K, V> getEntry(K key); V remove(K key); void removeNode(RedBlackEntry<K, V> node); void removeAll(); boolean isEmpty(); @Override ListIterator<RedBlackEntry<K, V>> iterator(); ListIterator<RedBlackEntry<K, V>> iterator(boolean forward); @SuppressWarnings("unchecked") ListIterator<RedBlackEntry<K, V>> iterator(RedBlackEntry<K, V> firstEntry,
			boolean forward); ListIterator<RedBlackEntry<K, V>> iterator(K key, boolean forward); void deleteEntry(RedBlackEntry<K, V> p);  }### Answer:
@Test public void testSize() { assertEquals(9, tree.size()); }