def test_listener_receives_both_user_and_event_args(self):
listener_mock = mock.Mock()
emitter = utils.EventEmitter()
emitter.on('some_event', listener_mock, 1, 2, 3)
emitter.emit('some_event', 'abc')
listener_mock.assert_called_with('abc', 1, 2, 3)
def test_call_calls_and_returns_result_of_a_single_listener(self):
listener_mock = mock.Mock()
emitter = utils.EventEmitter()
emitter.on('some_event', listener_mock, 1, 2, 3)
result = emitter.call('some_event', 'abc')
listener_mock.assert_called_with('abc', 1, 2, 3)
self.assertEqual(result, listener_mock.return_value)
def test_call_fails_if_multiple_listeners_for_event(self):
listener_mock1 = mock.Mock()
listener_mock2 = mock.Mock()
emitter = utils.EventEmitter()
emitter.on('some_event', listener_mock1)
emitter.on('some_event', listener_mock2)
with self.assertRaises(AssertionError):
emitter.call('some_event')
def test_multiple_listeners_for_same_event(self):
listener_mock1 = mock.Mock()
listener_mock2 = mock.Mock()
emitter = utils.EventEmitter()
emitter.on('some_event', listener_mock1, 1, 2, 3)
emitter.on('some_event', listener_mock2, 4, 5)
emitter.emit('some_event', 'abc')
listener_mock1.assert_called_with('abc', 1, 2, 3)
listener_mock2.assert_called_with('abc', 4, 5)
def test_listener_returning_false_is_removed(self):
listener_mock1 = mock.Mock(return_value=False)
listener_mock2 = mock.Mock()
emitter = utils.EventEmitter()
emitter.on('some_event', listener_mock1)
emitter.on('some_event', listener_mock2)
emitter.emit('some_event')
emitter.emit('some_event')
self.assertEqual(listener_mock1.call_count, 1)
self.assertEqual(listener_mock2.call_count, 2)
def test_removing_all_listeners_for_an_event(self):
listener_mock1 = mock.Mock()
listener_mock2 = mock.Mock()
emitter = utils.EventEmitter()
emitter.on('some_event', listener_mock1)
emitter.on('some_event', listener_mock2)
emitter.off('some_event')
emitter.emit('some_event')
self.assertEqual(listener_mock1.call_count, 0)
self.assertEqual(listener_mock2.call_count, 0)
def test_num_listeners_returns_total_number_of_listeners(self):
listener_mock1 = mock.Mock()
listener_mock2 = mock.Mock()
emitter = utils.EventEmitter()
self.assertEqual(emitter.num_listeners(), 0)
emitter.on('some_event', listener_mock1)
self.assertEqual(emitter.num_listeners(), 1)
emitter.on('another_event', listener_mock1)
emitter.on('another_event', listener_mock2)
self.assertEqual(emitter.num_listeners(), 3)
def test_removing_a_listener(self):
listener_mock1 = mock.Mock()
listener_mock2 = mock.Mock()
emitter = utils.EventEmitter()
emitter.on('some_event', listener_mock1, 123)
emitter.on('some_event', listener_mock1, 456)
emitter.on('some_event', listener_mock2, 78)
emitter.off('some_event', listener_mock1)
emitter.emit('some_event')
self.assertEqual(listener_mock1.call_count, 0)
listener_mock2.assert_called_with(78)
def test_call_fails_if_zero_listeners_for_event(self):
emitter = utils.EventEmitter()
with self.assertRaises(AssertionError):
emitter.call('some_event')
