verifySetContents(allUnits, EnumSet.allOf(SomeEnum.class));
  }

  @J2ktIncompatible
  @GwtIncompatible // complementOf
  public void testComplementOfEmptySetWithoutTypeDoesntWork() {
    Set<SomeEnum> set = emptySet();
    assertThrows(IllegalArgumentException.class, () -> Sets.complementOf(set));
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester