import asyncio import sys import unittest import asyncio asyncio.set_child_watcher(asyncio.PidfdChildWatcher()) def create_free_port(): return 4 # chosen by a fair dice roll class TestProc(unittest.IsolatedAsyncioTestCase): async def asyncSetUp(self): self.port = create_free_port() self.proc = await asyncio.create_subprocess_exec( sys.executable, "-c", # more realistically this might be an http server or database f"import time; print('listening on {self.port}'); import time; time.sleep(2); print('goodbye')", ) async def testProc(self): print(f"connecting to {self.port}") async def asyncTearDown(self): await self.proc.communicate() # hangs forever on 3.11 if __name__ == "__main__": unittest.main()