}

  public void testMutableValues() {
    IntHolder holderA = new IntHolder(1);
    IntHolder holderB = new IntHolder(2);
    Map<String, IntHolder> map = ImmutableMap.of("a", holderA, "b", holderB);
    holderA.value = 3;
    assertTrue(map.entrySet().contains(immutableEntry("a", new IntHolder(3))));
    Map<String, Integer> intMap = ImmutableMap.of("a", 3, "b", 2);