assertThrows(
          NullPointerException.class, () -> entries.toArray((Entry<Object, Object>[]) null));
      checkEmpty(cache);
    }
  }

  public void testEntrySet_addNotSupported() {
    for (LoadingCache<Object, Object> cache : caches()) {
      assertThrows(
          UnsupportedOperationException.class, () -> cache.asMap().entrySet().add(entryOf(1, 1)));

      assertThrows(