@Test
public void testAttributeRemoved() {

  notifier.attributeRemoved(session, "Test", "very-old-value");
  HttpSessionAttributeListener listener = mock(HttpSessionAttributeListener.class);
  descriptor.addHttpSessionAttributeListener(listener);
  notifier.attributeRemoved(session, "Test", "old-value");
  verify(listener).attributeRemoved(any(HttpSessionBindingEvent.class));
  HttpSessionBindingListener bindingListener = mock(HttpSessionBindingListener.class);
  notifier.attributeRemoved(session, "Test", bindingListener);
  verify(listener, times(2)).attributeRemoved(any(HttpSessionBindingEvent.class));
  verify(bindingListener).valueUnbound(any(HttpSessionBindingEvent.class));
}