new ForwardingWrapperTester()
        .testForwarding(
            Sub.class,
            new Function<Sub, Sub>() {
              @Override
              public Sub apply(Sub sub) {
                return new ForwardingSub(sub);
              }
            });
  }

  interface Base {
    CharSequence getId();
  }

  interface Sub extends Base {
    @Override
    String getId();
  }

    new ForwardingWrapperTester()
        .testForwarding(
            Sub.class,
            new Function<Sub, Sub>() {
              @Override
              public Sub apply(Sub sub) {
                return new ForwardingSub(sub);
              }
            });
  }

  interface Base {
    CharSequence getId();
  }

  interface Sub extends Base {
    @Override
    String getId();
  }