diff --git a/tests/test_run_app.py b/tests/test_run_app.py
index 622fa560e24..dab36942e49 100644
--- a/tests/test_run_app.py
+++ b/tests/test_run_app.py
@@ -1284,6 +1284,7 @@ async def run_test(app: web.Application) -> AsyncIterator[None]:
             nonlocal t
             t = asyncio.create_task(test())
             yield
+            await asyncio.sleep(0)  # In case test() hasn't resumed yet.
             t.cancel()
             with contextlib.suppress(asyncio.CancelledError):
                 await t