Client and Service Stubs take 1 request parameter, not one for each field (#311)

tests/inputs/import_service_input_message/test_import_service_input_message.py

@@ -1,17 +1,21 @@
 import pytest
-
 from tests.mocks import MockChannel
 from tests.output_betterproto.import_service_input_message import (
+    NestedRequestMessage,
+    RequestMessage,
     RequestResponse,
     TestStub,
 )
+from tests.output_betterproto.import_service_input_message.child import (
+    ChildRequestMessage,
+)
 
 
 @pytest.mark.asyncio
 async def test_service_correctly_imports_reference_message():
     mock_response = RequestResponse(value=10)
     service = TestStub(MockChannel([mock_response]))
-    response = await service.do_thing(argument=1)
+    response = await service.do_thing(RequestMessage(1))
     assert mock_response == response
 
 
@@ -19,7 +23,7 @@ async def test_service_correctly_imports_reference_message():
 async def test_service_correctly_imports_reference_message_from_child_package():
     mock_response = RequestResponse(value=10)
     service = TestStub(MockChannel([mock_response]))
-    response = await service.do_thing2(child_argument=1)
+    response = await service.do_thing2(ChildRequestMessage(1))
     assert mock_response == response
 
 
@@ -27,5 +31,5 @@ async def test_service_correctly_imports_reference_message_from_child_package():
 async def test_service_correctly_imports_nested_reference():
     mock_response = RequestResponse(value=10)
     service = TestStub(MockChannel([mock_response]))
-    response = await service.do_thing3(nested_argument=1)
+    response = await service.do_thing3(NestedRequestMessage(1))
     assert mock_response == response