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Concurrency & performance

asyncio, threading, multiprocessing, and profiling-friendly performance patterns.

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Concurrency & performance medium

How to Mock asyncio.open_connection in Python

Mock asyncio.open_connection with AsyncMock to test async code without a real network connection.

asyncio testing mocking
Python 
import asyncio
from unittest.mock import AsyncMock, patch


async def fetch_data(reader: asyncio.StreamReader) -> str:
    data = await reader.readline()
    return data.decode().strip()


async def main() -> None:
    # Mock asyncio.open_connection to simulate a server response
    mock_reader = AsyncMock()
    mock_…
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