Support testing unary-stream calls that return a coroutine

Originally testing unary-stream calls assumed a `GrpcStreamBroadcaster`
is used, which means a `Receiver` is returned synchronously. But not all
unary-stream calls adopt this pattern, and some might be async, so
returning a coroutine instead.

With this commit we inspect the return value and if it is a coroutine,
we await for it and assign the awaited value as the client result.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

tests/util.py

@@ -1001,6 +1001,10 @@ def create_response_wrapper(*_: Any, **__: Any) -> AsyncIterator[Any]:
             client_result = client_method(
                 *test_case.client_args, **test_case.client_kwargs
             )
+            if asyncio.iscoroutine(client_result):
+                _logger.debug("The client method is a coroutine, awaiting it...")
+                async with asyncio.timeout(60):
+                    client_result = await client_result
             _logger.debug("Client method result: %r", client_result)
         except Exception as err:  # pylint: disable=broad-exception-caught
             _logger.debug("Client method raised an exception: %r", err)