}
    assertInvariants(map);
  }

  @J2ktIncompatible // https://youtrack.jetbrains.com/issue/KT-58242/ undefined behavior (crash)
  public void testContainsKey() {
    Map<K, V> map;
    K unmappedKey;
    try {
      map = makePopulatedMap();
      unmappedKey = getKeyNotInPopulatedMap();
    } catch (UnsupportedOperationException e) {
      return;
    }