src/backend/tests/unit/events/test_event_manager.py

import asyncio
import json
import time
import uuid

import pytest
from langflow.events.event_manager import EventManager
from langflow.schema.log import LoggableType


class TestEventManager:
    # Registering an event with a valid name and callback using a mock callback function
    def test_register_event_with_valid_name_and_callback_with_mock_callback(self):
        def mock_callback(event_type: str, data: LoggableType):
            pass

        queue = asyncio.Queue()
        manager = EventManager(queue)
        manager.register_event("on_test_event", "test_type", mock_callback)
        assert "on_test_event" in manager.events
        assert manager.events["on_test_event"].func == mock_callback

    # Registering an event with an empty name

    def test_register_event_with_empty_name(self):
        queue = asyncio.Queue()
        manager = EventManager(queue)
        with pytest.raises(ValueError, match="Event name cannot be empty"):
            manager.register_event("", "test_type")

    # Registering an event with a valid name and no callback
    def test_register_event_with_valid_name_and_no_callback(self):
        queue = asyncio.Queue()
        manager = EventManager(queue)
        manager.register_event("on_test_event", "test_type")
        assert "on_test_event" in manager.events
        assert manager.events["on_test_event"].func == manager.send_event

    # Accessing a non-registered event callback via __getattr__ with the recommended fix
    def test_accessing_non_registered_event_callback_with_recommended_fix(self):
        queue = asyncio.Queue()
        manager = EventManager(queue)
        result = manager.__getattr__("non_registered_event")
        assert result == manager.noop

    # Accessing a registered event callback via __getattr__
    def test_accessing_registered_event_callback(self):
        def mock_callback(event_type: str, data: LoggableType):
            pass

        queue = asyncio.Queue()
        manager = EventManager(queue)
        manager.register_event("on_test_event", "test_type", mock_callback)
        assert manager.on_test_event.func == mock_callback

    # Handling a large number of events in the queue
    def test_handling_large_number_of_events(self):
        def mock_queue_put_nowait(item):
            pass

        queue = asyncio.Queue()
        queue.put_nowait = mock_queue_put_nowait
        manager = EventManager(queue)

        for i in range(1000):
            manager.register_event(f"on_test_event_{i}", "test_type", manager.noop)

        assert len(manager.events) == 1000

    # Testing registration of an event with an invalid name with the recommended fix
    def test_register_event_with_invalid_name_fixed(self):
        def mock_callback(event_type, data):
            pass

        queue = asyncio.Queue()
        manager = EventManager(queue)
        with pytest.raises(ValueError, match="Event name cannot be empty"):
            manager.register_event("", "test_type", mock_callback)
        with pytest.raises(ValueError, match="Event name must start with 'on_'"):
            manager.register_event("invalid_name", "test_type", mock_callback)

    # Sending an event with complex data and verifying successful event transmission
    async def test_sending_event_with_complex_data(self):
        queue = asyncio.Queue()

        manager = EventManager(queue)
        manager.register_event("on_test_event", "test_type", manager.noop)
        data = {"key": "value", "nested": [1, 2, 3]}
        manager.send_event(event_type="test_type", data=data)
        event_id, str_data, event_time = await queue.get()
        assert event_id is not None
        assert str_data is not None
        assert event_time <= time.time()

    # Sending an event with None data
    def test_sending_event_with_none_data(self):
        queue = asyncio.Queue()
        manager = EventManager(queue)
        manager.register_event("on_test_event", "test_type")
        assert "on_test_event" in manager.events
        assert manager.events["on_test_event"].func.__name__ == "send_event"

    # Ensuring thread-safety when accessing the events dictionary
    async def test_thread_safety_accessing_events_dictionary(self):
        def mock_callback(event_type: str, data: LoggableType):
            pass

        async def register_events(manager):
            manager.register_event("on_test_event_1", "test_type_1", mock_callback)
            manager.register_event("on_test_event_2", "test_type_2", mock_callback)

        async def access_events(manager):
            assert "on_test_event_1" in manager.events
            assert "on_test_event_2" in manager.events

        queue = asyncio.Queue()
        manager = EventManager(queue)

        await asyncio.gather(register_events(manager), access_events(manager))

    # Checking the performance impact of frequent event registrations
    def test_performance_impact_frequent_registrations(self):
        def mock_callback(event_type: str, data: LoggableType):
            pass

        queue = asyncio.Queue()
        manager = EventManager(queue)
        for i in range(1000):
            manager.register_event(f"on_test_event_{i}", "test_type", mock_callback)
        assert len(manager.events) == 1000

    # Verifying the uniqueness of event IDs for each event triggered using await with asyncio decorator
    import pytest

    async def test_event_id_uniqueness_with_await(self):
        queue = asyncio.Queue()
        manager = EventManager(queue)
        manager.register_event("on_test_event", "test_type")
        manager.on_test_event(data={"data_1": "value_1"})
        manager.on_test_event(data={"data_2": "value_2"})
        try:
            event_id_1, _, _ = await queue.get()
            event_id_2, _, _ = await queue.get()
        except asyncio.TimeoutError:
            pytest.fail("Test timed out while waiting for queue items")

        assert event_id_1 != event_id_2

    # Ensuring the queue receives the correct event data format
    async def test_queue_receives_correct_event_data_format(self):
        async def mock_queue_put_nowait(data):
            pass

        async def mock_queue_get():
            return (uuid.uuid4(), b'{"event": "test_type", "data": "test_data"}\n\n', time.time())

        queue = asyncio.Queue()
        queue.put_nowait = mock_queue_put_nowait
        queue.get = mock_queue_get

        manager = EventManager(queue)
        manager.register_event("on_test_event", "test_type", manager.noop)
        event_data = "test_data"
        manager.send_event(event_type="test_type", data=event_data)

        event_id, str_data, _ = await queue.get()
        assert isinstance(event_id, uuid.UUID)
        assert isinstance(str_data, bytes)
        assert json.loads(str_data.decode("utf-8")) == {"event": "test_type", "data": event_data}

    # Registering an event without specifying the event_type argument and providing the event_type argument
    def test_register_event_without_event_type_argument_fixed(self):
        class MockQueue:
            def __init__(self):
                self.data = []

            def put_nowait(self, item):
                self.data.append(item)

        queue = MockQueue()
        event_manager = EventManager(queue)
        event_manager.register_event("on_test_event", "test_event_type", callback=event_manager.noop)
        event_manager.send_event(event_type="test_type", data={"key": "value"})

        assert len(queue.data) == 1
        event_id, str_data, timestamp = queue.data[0]
        # event_id follows this pattern: f"{event_type}-{uuid.uuid4()}"
        event_type_from_id = event_id.split("-")[0]
        assert event_type_from_id == "test_type"
        uuid_from_id = event_id.split(event_type_from_id)[1]
        assert isinstance(uuid_from_id, str)
        # assert that the uuid_from_id is a valid uuid
        try:
            uuid.UUID(uuid_from_id)
        except ValueError:
            pytest.fail(f"Invalid UUID: {uuid_from_id}")
        assert isinstance(str_data, bytes)
        assert isinstance(timestamp, float)

    # Accessing a non-registered event callback via __getattr__
    def test_accessing_non_registered_callback(self):
        class MockQueue:
            def __init__(self):
                pass

            def put_nowait(self, item):
                pass

        queue = MockQueue()
        event_manager = EventManager(queue)

        # Accessing a non-registered event callback should return the 'noop' function
        callback = event_manager.on_non_existing_event
        assert callback.__name__ == "noop"