### Question:
OSGIPluginTracker { public boolean removeDelayedServiceNotifierListener( DelayedServiceNotifierListener delayedServiceNotifierListener ) { return aggregatingNotifierListener.removeListener( delayedServiceNotifierListener ); } @VisibleForTesting protected  OSGIPluginTracker(); @VisibleForTesting protected  OSGIPluginTracker( AggregatingNotifierListener aggregatingNotifierListener ); static OSGIPluginTracker getInstance(); List<T> getServiceObjects( Class<T> clazz, Map<String, String> props ); T getBean( Class<T> clazz, Object serviceClass, String id ); Object getBeanPluginProperty( Class<? extends PluginTypeInterface> pluginType,
                                                                       Object instance, String prop ); ClassLoader getClassLoader( Object instance ); void setBeanFactoryLookup( BeanFactoryLocator lookup ); ProxyUnwrapper getProxyUnwrapper(); void setProxyUnwrapper( ProxyUnwrapper proxyUnwrapper ); BeanFactory findOrCreateBeanFactoryFor( Object serviceObject ); void shutdown(); void addPluginLifecycleListener( Class clazzToTrack, OSGIServiceLifecycleListener listener ); BundleContext getBundleContext(); void setBundleContext( BundleContext context ); boolean registerPluginClass( Class clazz ); void serviceChanged( Class<?> cls, LifecycleEvent evt, ServiceReference serviceObject ); boolean addDelayedServiceNotifierListener( DelayedServiceNotifierListener delayedServiceNotifierListener ); boolean removeDelayedServiceNotifierListener( DelayedServiceNotifierListener delayedServiceNotifierListener ); int getOutstandingServiceNotifierListeners();  }### Answer:
@Test public void testRemoveDelayedServiceNotifierListener() { DelayedServiceNotifierListener delayedServiceNotifierListener = mock( DelayedServiceNotifierListener.class ); tracker.removeDelayedServiceNotifierListener( delayedServiceNotifierListener ); verify( aggregatingNotifierListener ).removeListener( delayedServiceNotifierListener ); }