registry.register(new ObjectSubscriber());
    assertEquals(2, registry.getSubscribersForTesting(String.class).size());
    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);

    }

    // Test default constructor
    @Test
    public void test_constructor() {
        assertNotNull(testScriptEngine);
    }

    // Test register method
    @Test
    public void test_register() {
        testScriptEngine.register();

        // Verify that the engine was registered with the factory
        ScriptEngine retrievedEngine = scriptEngineFactory.getScriptEngine("testEngine");