TaskGroup.cancel_remaining must wait for the tasks

Add test that cancel_remaining waits

aiorpcx/curio.py

@@ -41,6 +41,7 @@
     CancelledError, get_event_loop, Queue, Event, sleep, Task
 )
 from collections import deque
+from contextlib import suppress
 from functools import partial
 
 from aiorpcx.util import normalize_corofunc, check_task
@@ -243,7 +244,8 @@ async def cancel_remaining(self):
         pending = list(self._pending)
         for task in pending:
             task.cancel()
-        await sleep(0)
+            with suppress(CancelledError):
+                await task
 
     def __aiter__(self):
         return self

tests/test_curio.py

@@ -1,5 +1,5 @@
 from asyncio import (
-    sleep, CancelledError, get_event_loop, Event, InvalidStateError,
+    sleep, CancelledError, get_event_loop, Event, InvalidStateError
 )
 import time
 
@@ -1381,6 +1381,22 @@ async def main():
     await main()
 
 
+@pytest.mark.asyncio
+async def test_task_group_cancel_remaining_waits():
+    async def sleep_soundly():
+        try:
+            await sleep(0.01)
+        except CancelledError:
+            await sleep(0.01)
+
+    task = await spawn(sleep_soundly)
+    with pytest.raises(CancelledError):
+        async with TaskGroup([task]) as g:
+            await sleep(0)  # ensure the tasks are scheduled
+            raise CancelledError
+    assert task.done()
+
+
 @pytest.mark.asyncio
 async def test_task_group_use_error():
     async def main():