@SuppressWarnings("UseCollectionConstructor") // test of factory method
    HashMap<Object, Object> map = Maps.newHashMap(original);
    assertEquals(original, map);
  }

  public void testCapacityForNegativeSizeFails() {
    assertThrows(IllegalArgumentException.class, () -> Maps.capacity(-1));
  }

  /**
   * Tests that nHMWES makes hash maps large enough that adding the expected number of elements