CopyOnWriteArraySet<Integer> set = Sets.newCopyOnWriteArraySet(SOME_ITERABLE);
    verifySetContents(set, SOME_COLLECTION);
  }

  @J2ktIncompatible
  @GwtIncompatible // complementOf
  public void testComplementOfEnumSet() {
    Set<SomeEnum> units = EnumSet.of(SomeEnum.B, SomeEnum.D);
    EnumSet<SomeEnum> otherUnits = Sets.complementOf(units);
    verifySetContents(otherUnits, EnumSet.of(SomeEnum.A, SomeEnum.C));
  }