[PR #8309/c29945a1 backport][3.9] Improve reliability of run_app test (…

…#8315)

**This is a backport of PR #8309 as merged into master
(c29945a).**

Co-authored-by: Sam Bull <git@sambull.org>

tests/test_run_app.py

@@ -916,10 +916,16 @@ async def stop(self, request: web.Request) -> web.Response:
 
  def run_app(self, port: int, timeout: int, task, extra_test=None) -> asyncio.Task:
  async def test() -> None:
- await asyncio.sleep(1)
+ await asyncio.sleep(0.5)
  async with ClientSession() as sess:
- async with sess.get(f"http://localhost:{port}/"):
- pass
+ for _ in range(5): # pragma: no cover
+ try:
+ async with sess.get(f"http://localhost:{port}/"):
+ pass
+ except ClientConnectorError:
+ await asyncio.sleep(0.5)
+ else:
+ break
  async with sess.get(f"http://localhost:{port}/stop"):
  pass