### Question:
ConfigurationImpl implements Configuration { @Override public boolean isRegistered(Object obj) { for (Object o : getInstances()) { if (o.equals(obj)) { return true; } } return false; } ConfigurationImpl(RuntimeType rt);  ConfigurationImpl(Configuration parent); @Override Set<Class<?>> getClasses(); @Override Map<Class<?>, Integer> getContracts(Class<?> cls); @Override Set<Object> getInstances(); @Override Map<String, Object> getProperties(); @Override Object getProperty(String name); @Override Collection<String> getPropertyNames(); @Override RuntimeType getRuntimeType(); @Override boolean isEnabled(Feature f); @Override boolean isEnabled(Class<? extends Feature> f); @Override boolean isRegistered(Object obj); @Override boolean isRegistered(Class<?> cls); void setProperty(String name, Object value); void setFeature(Feature f, boolean enabled); boolean register(Object provider, Map<Class<?>, Integer> contracts); static Map<Class<?>, Integer> initContractsMap(int bindingPriority, Class<?>... contracts); static Object createProvider(Class<?> cls);  }### Answer:
@Test public void testIsRegistered() throws Exception { doTestIsFilterRegistered(new ContainerResponseFilterImpl(), ContainerResponseFilterImpl.class); }