OrderedSet implements Set<E> { public boolean isEmpty() { return set.isEmpty(); } OrderedSet();  OrderedSet(Collection<E> set);  OrderedSet(int initialCapacity); Object[] toArray(); boolean removeAll(Collection<?> c); T[] toArray(T[] a); Iterator<E> iterator(); int size(); boolean isEmpty(); boolean contains(Object o); boolean add(E o); boolean remove(Object o); void clear(); @Override Object clone(); boolean containsAll(Collection<?> c); boolean addAll(Collection<? extends E> c); boolean retainAll(Collection<?> c); @Override String toString(); @Override boolean equals(Object obj); @Override int hashCode();  }
@Test public void shouldConstruct() { OrderedSet<String> set = new OrderedSet<String>(); assertTrue(set.isEmpty()); }