Set<Set<Integer>> powerSet = powerSet(elements);
    assertEquals(1, powerSet.size());
    assertEquals(ImmutableSet.of(ImmutableSet.of()), powerSet);
    assertEquals(0, powerSet.hashCode());
  }

  public void testPowerSetContents() {
    ImmutableSet<Integer> elements = ImmutableSet.of(1, 2, 3);
    Set<Set<Integer>> powerSet = powerSet(elements);
    assertEquals(8, powerSet.size());

        return inputSet.keySet().containsAll(set);
      }
      return false;
    }

    @Override
    public boolean equals(@Nullable Object obj) {
      if (obj instanceof PowerSet) {
        PowerSet<?> that = (PowerSet<?>) obj;
        return inputSet.keySet().equals(that.inputSet.keySet());
      }
      return super.equals(obj);
    }

    @Override
    public int hashCode() {
      /*

  public void testContainsAll() {
    ImmutableSortedSet<Integer> set = ContiguousSet.create(Range.closed(1, 3), integers());
    for (Set<Integer> subset : Sets.powerSet(ImmutableSet.of(1, 2, 3))) {
      assertTrue(set.containsAll(subset));
    }
    for (Set<Integer> subset : Sets.powerSet(ImmutableSet.of(1, 2, 3))) {
      assertFalse(set.containsAll(Sets.union(subset, ImmutableSet.of(9))));
    }
  }

  public void testContainsAll() {
    ImmutableSortedSet<Integer> set = ContiguousSet.create(Range.closed(1, 3), integers());
    for (Set<Integer> subset : Sets.powerSet(ImmutableSet.of(1, 2, 3))) {
      assertTrue(set.containsAll(subset));
    }
    for (Set<Integer> subset : Sets.powerSet(ImmutableSet.of(1, 2, 3))) {
      assertFalse(set.containsAll(Sets.union(subset, ImmutableSet.of(9))));
    }
  }