new EqualsTester()
        .addEqualityGroup(function, SerializableTester.reserialize(function))
        .addEqualityGroup(Functions.forMap(map, 1))
        .testEquals();
  }

  public void testForMapWildCardWithDefault() {
    Map<String, Integer> map = new HashMap<>();
    map.put("One", 1);
    map.put("Three", 3);
    Number number = Double.valueOf(42);