def test_once_does_not_emits_error_when_not_listening_for_errors(
ee: EventEmitter, error_helper: "EEExceptionHelper") -> None:
ee.once("event", error_helper.error_raiser)
assert ee.listener_count("event") == 1
assert ee.listener_count("error") == 0
assert ee.emit("event", 1, data=2)
error_helper.assert_error_was_not_emitted()
assert ee.listener_count("event") == 0
assert ee.listener_count("error") == 0
def test_once(ee: EventEmitter, mock: Mock) -> None:
ee.once("event", mock.method)
assert ee.listener_count("event") == 1
assert mock.method is ee.listeners("event")[0]
assert ee.emit("event", 1, data=2)
assert not ee.emit("event", 1, data=2)
mock.method.assert_called_once_with(1, data=2)
assert ee.listener_count("event") == 0
assert mock.method not in ee.listeners("event")
async def test_coroutine_listener_once(ee_with_event_loop: EventEmitter,
mock: Mock, deferred: Future) -> None:
async def handler(*args, **kwargs) -> None:
mock.method(*args, **kwargs)
deferred.set_result(True)
ee_with_event_loop.once("event", handler)
assert ee_with_event_loop.listener_count("event") == 1
assert handler is ee_with_event_loop.listeners("event")[0]
assert ee_with_event_loop.emit("event", 1, data=2)
assert await deferred
assert not ee_with_event_loop.emit("event", 1, data=2)
mock.method.assert_called_once_with(1, data=2)
assert ee_with_event_loop.listener_count("event") == 0
assert handler not in ee_with_event_loop.listeners("event")
