Add timeout to streaming test

tests/test_streaming.py

@@ -79,6 +79,7 @@ async def stream_from_single_subactor(
 
                 seq = range(10)
 
+                with trio.fail_after(5):
                     async with portal.open_stream_from(
                         stream_func,
                         sequence=list(seq),  # has to be msgpack serializable
@@ -100,12 +101,14 @@ async def stream_from_single_subactor(
 
                         await trio.sleep(0.3)
 
+                        # ensure EOC signalled-state translates
+                        # XXX: not really sure this is correct,
+                        # shouldn't it be a `ClosedResourceError`?
                         try:
                             await stream.__anext__()
                         except StopAsyncIteration:
                             # stop all spawned subactors
                             await portal.cancel_actor()
-                    # await nursery.cancel()
 
 
 @pytest.mark.parametrize(