assertEquals(1, registry.getSubscribersForTesting(Object.class).size());
  }

  public void testUnregister() {
    StringSubscriber s1 = new StringSubscriber();
    StringSubscriber s2 = new StringSubscriber();

    registry.register(s1);
    registry.register(s2);

    registry.unregister(s1);
    assertEquals(1, registry.getSubscribersForTesting(String.class).size());