def test_emit_event_implement_follows_intercept(self):
EVENT_NAME = "event.hello.world"
callback_tracker = ['']
def my_callback_intcpt(event_args, *args, **kwargs):
self.assertEqual(event_args.get('sender'), self)
next_handler = event_args.get('next_handler')
self.assertEqual(next_handler.priority, 2020)
self.assertEqual(next_handler.callback.__name__,
"my_callback_impl")
callback_tracker[0] += "intcpt_"
# invoke next handler but ignore return value
return "hello" + next_handler.invoke(event_args, *args, **kwargs)
def my_callback_impl(*args, **kwargs):
self.assertSequenceEqual(args, ['first_pos_arg'])
self.assertDictEqual(kwargs, {'a_keyword_arg': 'another_thing'})
callback_tracker[0] += "impl_"
return "world"
dispatcher = SimpleEventDispatcher()
dispatcher.intercept(EVENT_NAME, 2000, my_callback_intcpt)
dispatcher.implement(EVENT_NAME, 2020, my_callback_impl)
result = dispatcher.dispatch(self,
EVENT_NAME,
'first_pos_arg',
a_keyword_arg='another_thing')
self.assertEqual(
callback_tracker[0], "intcpt_impl_", "callback was not invoked"
" in expected order. Should have been intcpt_impl_ but is"
" {0}".format(callback_tracker[0]))
self.assertEqual(
result, "helloworld", "Result should be `helloworld` "
"as this is the expected return value from the chain")
def test_emit_event_implementing_handler(self):
EVENT_NAME = "event.hello.world"
callback_tracker = ['']
def my_callback(*args, **kwargs):
self.assertSequenceEqual(args, ['first_pos_arg'])
self.assertDictEqual(kwargs, {'a_keyword_arg': 'another_thing'})
callback_tracker[0] += "impl"
return "world"
dispatcher = SimpleEventDispatcher()
handler = dispatcher.implement(event_pattern=EVENT_NAME,
priority=1000,
callback=my_callback)
self.assertIsInstance(handler, EventHandler)
result = dispatcher.dispatch(self,
EVENT_NAME,
'first_pos_arg',
a_keyword_arg='another_thing')
self.assertEqual(
callback_tracker[0], "impl", "callback should have been invoked"
"once and contain value `intcpt` but tracker value is {0}".format(
callback_tracker[0]))
self.assertEqual(
result, "world", "Result should be `world` as this"
" is an implementing handler")
def test_emit_event_implement_precedes_intercept(self):
EVENT_NAME = "event.hello.world"
callback_tracker = ['']
def my_callback_intcpt(event_args, *args, **kwargs):
# Impl result should be accessible to intercepts that follow
self.assertDictEqual(
event_args, {
'sender': self,
'event': EVENT_NAME,
'result': 'world',
'next_handler': None
})
self.assertSequenceEqual(args, ['first_pos_arg'])
self.assertDictEqual(kwargs, {'a_keyword_arg': 'another_thing'})
callback_tracker[0] += "intcpt_"
return "hello"
def my_callback_impl(*args, **kwargs):
self.assertSequenceEqual(args, ['first_pos_arg'])
self.assertDictEqual(kwargs, {'a_keyword_arg': 'another_thing'})
callback_tracker[0] += "impl_"
return "world"
dispatcher = SimpleEventDispatcher()
dispatcher.implement(EVENT_NAME, 2000, my_callback_impl)
dispatcher.intercept(EVENT_NAME, 2020, my_callback_intcpt)
result = dispatcher.dispatch(self,
EVENT_NAME,
'first_pos_arg',
a_keyword_arg='another_thing')
self.assertEqual(
callback_tracker[0], "impl_intcpt_", "callback was not invoked"
" in expected order. Should have been intcpt_intcpt_ but is"
" {0}".format(callback_tracker[0]))
self.assertEqual(
result, "world", "Result should be `world` "
"as this is the expected return value from the chain")