def test_pubsub_register_and_unregister():
pubsub = PubSub()
channel_id = pubsub.register()
assert pubsub.size() == 1
assert isinstance(channel_id, str)
channel_id2 = pubsub.register()
assert pubsub.size() == 2
assert channel_id != channel_id2
pubsub.delete(channel_id)
assert channel_id not in pubsub._channels
assert pubsub.size() == 1
pubsub.delete(channel_id2)
assert channel_id2 not in pubsub._channels
def test_pubsub_create():
pubsub = PubSub()
assert pubsub.size() == 0