### Question:
BST { public int size() { return getCount(root); }  int size(); boolean isEmpty(); boolean contains(Key key); Val find(Key key); void put(Key key, Val val); boolean remove(Key key); Key select(int rank); int rank(Key key); Key floor(Key key); Key ceil(Key key);  }### Answer:
@Test public void size() { Assert.assertEquals(expect.size(), bst.size()); }