assertTrue(set.contains(value1));
    assertTrue(set.add(value2));
    assertEquals(2, set.size());
  }

  @J2ktIncompatible
  @GwtIncompatible // CopyOnWriteArraySet
  public void testNewCOWASEmpty() {
    CopyOnWriteArraySet<Integer> set = Sets.newCopyOnWriteArraySet();
    verifySetContents(set, EMPTY_COLLECTION);
  }

  @J2ktIncompatible
  @GwtIncompatible // CopyOnWriteArraySet