[DO NOT MERGE] Test case for object serde round-tripping

tests/grpc/test_grpclib_client.py

@@ -15,6 +15,7 @@
     DoThingResponse,
     GetThingRequest,
     TestStub as ThingServiceClient,
+    ThingType,
 )
 
 from .thing_service import ThingService
@@ -52,6 +53,24 @@ async def test_simple_service_call():
     async with ChannelFor([ThingService()]) as channel:
         await _test_client(ThingServiceClient(channel))
 
+@pytest.mark.asyncio
+async def test_messages_roundtrip_with_default_fields():
+    async with ChannelFor([ThingService()]) as channel:
+        client = ThingServiceClient(channel)
+        request = DoThingRequest("name", ["comment"], ThingType.UNKNOWN, 0) # UNKNOWN and 0 are protobuf default values
+        response = await client.do_thing(request)
+
+        # Assert we get back the request
+        assert request == response.request
+        assert response.names == ["name"]
+        assert response.request.number == 0
+        assert response.request.type == ThingType.UNKNOWN
+        assert id(request) != id(response.request) # prove that objects went through serde
+
+        # Try with a newly construction request object
+        expected_request = DoThingRequest("name", ["comment"], ThingType.UNKNOWN, 0)
+        assert expected_request == response.request
+
 
 @pytest.mark.asyncio
 async def test_trailer_only_error_unary_unary(

tests/grpc/thing_service.py

@@ -22,7 +22,7 @@ async def do_thing(
         request = await stream.recv_message()
         if self.test_hook is not None:
             self.test_hook(stream)
-        await stream.send_message(DoThingResponse([request.name]))
+        await stream.send_message(DoThingResponse([request.name], request))
 
     async def do_many_things(
         self, stream: "grpclib.server.Stream[DoThingRequest, DoThingResponse]"

tests/inputs/service/service.proto

@@ -12,10 +12,12 @@ message DoThingRequest {
   string name = 1;
   repeated string comments = 2;
   ThingType type = 3;
+  int32 number = 4;
 }
 
 message DoThingResponse {
   repeated string names = 1;
+  DoThingRequest request = 2;
 }
 
 message GetThingRequest {