try {
      // even to the same value is not allowed
      maker.initialCapacity(16);
      fail();
    } catch (IllegalStateException expected) {
    }
  }

  public void testReturnsPlainConcurrentHashMapWhenPossible() {
    Map<?, ?> map = new MapMaker().initialCapacity(5).makeMap();
    assertTrue(map instanceof ConcurrentHashMap);
  }