### Question:
PropertysetItem implements Item, Item.PropertySetChangeNotifier,
        Cloneable { @Override public void removePropertySetChangeListener( Item.PropertySetChangeListener listener) { if (propertySetChangeListeners != null) { propertySetChangeListeners.remove(listener); } }  @Override Property getItemProperty(Object id); @Override Collection<?> getItemPropertyIds(); @Override boolean removeItemProperty(Object id); @Override boolean addItemProperty(Object id, Property property); @Override String toString(); @Override void addPropertySetChangeListener(
            Item.PropertySetChangeListener listener); @Override void removePropertySetChangeListener(
            Item.PropertySetChangeListener listener); Collection<?> getListeners(Class<?> eventType); @Override Object clone(); @Override boolean equals(Object obj); @Override int hashCode();  }### Answer:
@Test public void testRemoveNonExistentListener() { PropertysetItem item = createPropertySetItem(); item.removePropertySetChangeListener(propertySetListenerMock); }