initMapWithNullValue();
    assertTrue(
        "containsKey(keyForNullValue) should return true",
        getMap().containsKey(getKeyForNullValue()));
  }

  public void testContains_wrongType() {
    try {
      // noinspection SuspiciousMethodCalls
      assertFalse(
          "containsKey(wrongType) should return false or throw",
          getMap().containsKey(WrongType.VALUE));