return key;
    }
  }

  /*
   * TODO(cpovirk): eliminate duplication between these tests and those in LegacyMapMakerTests and
   * anywhere else
   */

  public void testInitialCapacity_negative() {
    MapMaker maker = new MapMaker();
    assertThrows(IllegalArgumentException.class, () -> maker.initialCapacity(-1));
  }