def create_notifier(**kwargs):
""" Convenient function for creating an instance of TraitEventNotifier
for testing purposes.
"""
values = dict(
handler=mock.Mock(),
target=_DUMMY_TARGET,
event_factory=mock.Mock(),
prevent_event=not_prevent_event,
dispatcher=dispatch_here,
)
values.update(kwargs)
return TraitEventNotifier(**values)
def get_notifier(self, handler, target, dispatcher):
""" Return a notifier for calling the user handler with the change
event.
Returns
-------
notifier : TraitEventNotifier
"""
return TraitEventNotifier(
handler=handler,
target=target,
dispatcher=dispatcher,
event_factory=set_event_factory,
prevent_event=lambda event: False,
)
def get_notifier(self, handler, target, dispatcher):
""" Return a notifier for calling the user handler with the change
event.
Returns
-------
notifier : TraitEventNotifier
"""
# Unlike CTrait, when default dict is created, there isn't a change
# event where the old value is Uninitialized.
return TraitEventNotifier(
handler=handler,
target=target,
dispatcher=dispatcher,
event_factory=dict_event_factory,
prevent_event=lambda event: False,
)
def get_notifier(self, handler, target, dispatcher):
""" Return a notifier for calling the user handler with the change
event.
If the old value is uninitialized, then the change is caused by having
the default value defined. Such an event is prevented from reaching the
user's change handler.
Returns
-------
notifier : TraitEventNotifier
"""
return TraitEventNotifier(
handler=handler,
target=target,
dispatcher=dispatcher,
event_factory=trait_event_factory,
prevent_event=lambda event: event.old is Uninitialized,
)