[Chore] Separate out vllm.utils.async_utils (#26913)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

tests/utils_/test_utils.py

@@ -2,14 +2,12 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 # ruff: noqa
 
-import asyncio
 import hashlib
 import json
 import os
 import pickle
 import socket
 import tempfile
-from collections.abc import AsyncIterator
 from pathlib import Path
 from unittest.mock import patch
 
@@ -37,7 +35,6 @@ from vllm.utils import (
     make_zmq_path,
     make_zmq_socket,
     memory_profiling,
-    merge_async_iterators,
     sha256,
     split_host_port,
     split_zmq_path,
@@ -48,39 +45,6 @@ from vllm.utils import (
 from ..utils import create_new_process_for_each_test
 
 
-@pytest.mark.asyncio
-async def test_merge_async_iterators():
-    async def mock_async_iterator(idx: int):
-        try:
-            while True:
-                yield f"item from iterator {idx}"
-                await asyncio.sleep(0.1)
-        except asyncio.CancelledError:
-            print(f"iterator {idx} cancelled")
-
-    iterators = [mock_async_iterator(i) for i in range(3)]
-    merged_iterator = merge_async_iterators(*iterators)
-
-    async def stream_output(generator: AsyncIterator[tuple[int, str]]):
-        async for idx, output in generator:
-            print(f"idx: {idx}, output: {output}")
-
-    task = asyncio.create_task(stream_output(merged_iterator))
-    await asyncio.sleep(0.5)
-    task.cancel()
-    with pytest.raises(asyncio.CancelledError):
-        await task
-
-    for iterator in iterators:
-        try:
-            await asyncio.wait_for(anext(iterator), 1)
-        except StopAsyncIteration:
-            # All iterators should be cancelled and print this message.
-            print("Iterator was cancelled normally")
-        except (Exception, asyncio.CancelledError) as e:
-            raise AssertionError() from e
-
-
 def test_get_open_port(monkeypatch: pytest.MonkeyPatch):
     with monkeypatch.context() as m:
         m.setenv("VLLM_PORT", "5678")