### Question:
RangeSet implements IntSet { @Override public boolean containsAll(Collection<?> c) { if (c instanceof IntSet) { return containsAll((IntSet) c); } for (Object o : c) { if (!contains(o)) return false; } return true; } RangeSet(int size); @Override int size(); @Override boolean isEmpty(); @Override boolean contains(Object o); @Override boolean contains(int i); @Override PrimitiveIterator.OfInt iterator(); @Override int[] toIntArray(); @Override Object[] toArray(); @Override T[] toArray(T[] a); @Override boolean add(Integer integer); @Override boolean remove(Object o); @Override boolean remove(int i); @Override boolean containsAll(Collection<?> c); @Override boolean containsAll(IntSet set); @Override boolean add(int i); void set(int i); @Override boolean addAll(IntSet set); @Override boolean addAll(Collection<? extends Integer> c); @Override boolean retainAll(Collection<?> c); @Override boolean retainAll(IntSet c); @Override boolean removeAll(IntSet set); @Override boolean removeAll(Collection<?> c); @Override void clear(); @Override boolean equals(Object o); @Override IntStream intStream(); @Override void forEach(IntConsumer action); @Override void forEach(Consumer<? super Integer> action); @Override Spliterator.OfInt intSpliterator(); @Override boolean removeIf(IntPredicate filter); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void containsAll() throws Exception { RangeSet rs = new RangeSet(4); RangeSet rs2 = new RangeSet(4); assertTrue(rs.containsAll(rs2)); RangeSet rs3 = new RangeSet(3); assertTrue(rs.containsAll(rs3)); assertFalse(rs3.containsAll(rs)); }