[+!] all but small

some small modifications, tests added

tests/entrypoint_runner.py

@@ -0,0 +1,41 @@
+"""Execute the real entrypoint with a private TCP binding and graceful test shutdown.
+
+Only asyncio.start_server's binding arguments are redirected. Its real server,
+TCP.run, handler, manager, router, protocol and background sends all run normally.
+The stdin task cancels main just as an external stop would, allowing coverage's
+atexit hook to save child measurements on Windows as well as Linux.
+"""
+
+import asyncio
+from pathlib import Path
+import runpy
+import sys
+
+
+async def stop_from_stdin(main_task):
+    await asyncio.to_thread(sys.stdin.buffer.readline)
+    main_task.cancel()
+
+
+def run():
+    main = Path(sys.argv[1]).resolve()
+    original_start_server = asyncio.start_server
+
+    async def start_server(callback, host=None, port=None, **kwargs):
+        server = await original_start_server(callback, "127.0.0.1", 0, **kwargs)
+        address = server.sockets[0].getsockname()
+        asyncio.create_task(stop_from_stdin(asyncio.current_task()))
+        print(f"TCP listening {address[0]}:{address[1]}", flush=True)
+        return server
+
+    asyncio.start_server = start_server
+    sys.path.insert(0, str(main.parent))
+    sys.argv = [str(main)]
+    try:
+        runpy.run_path(str(main), run_name="__main__")
+    except asyncio.CancelledError:
+        pass
+
+
+if __name__ == "__main__":
+    run()