import unittest

from unittest.mock import Mock

from IPython.core import events

import IPython.testing.tools as tt

@events._define_event

def ping_received():

pass

@events._define_event

def event_with_argument(argument):

pass

class CallbackTests(unittest.TestCase):

def setUp(self):

self.em = events.EventManager(

get_ipython(),

{

"ping_received": ping_received,

"event_with_argument": event_with_argument,

},

)

def test_register_unregister(self):

cb = Mock()

self.em.register("ping_received", cb)

self.em.trigger("ping_received")

self.assertEqual(cb.call_count, 1)

self.em.unregister("ping_received", cb)

self.em.trigger("ping_received")

self.assertEqual(cb.call_count, 1)

def test_bare_function_missed_unregister(self):

def cb1():

...

def cb2():

...

self.em.register("ping_received", cb1)

self.assertRaises(ValueError, self.em.unregister, "ping_received", cb2)

self.em.unregister("ping_received", cb1)

def test_cb_error(self):

cb = Mock(side_effect=ValueError)

self.em.register("ping_received", cb)

with tt.AssertPrints("Error in callback"):

self.em.trigger("ping_received")

def test_cb_keyboard_interrupt(self):

cb = Mock(side_effect=KeyboardInterrupt)

self.em.register("ping_received", cb)

with tt.AssertPrints("Error in callback"):

self.em.trigger("ping_received")

def test_unregister_during_callback(self):

invoked = [False] * 3

def func1(*_):

invoked[0] = True

self.em.unregister("ping_received", func1)

self.em.register("ping_received", func3)

def func2(*_):

invoked[1] = True

self.em.unregister("ping_received", func2)

def func3(*_):

invoked[2] = True

self.em.register("ping_received", func1)

self.em.register("ping_received", func2)

self.em.trigger("ping_received")

self.assertEqual([True, True, False], invoked)

self.assertEqual([func3], self.em.callbacks["ping_received"])