chore: refactor request type tests (#17026)

This PR depends on #16944. Please review #16944 first.

This PR addresses the feedback in
#16944 (comment)

Author: parthea

packages/gapic-generator/gapic/templates/tests/unit/gapic/%name_%version/%sub/test_macros.j2

@@ -1,30 +1,29 @@
 {% macro grpc_required_tests(method, service, api, full_extended_lro=False) %}
+{%- set method_settings = api.all_method_settings.get(method.meta.address.proto) -%}
+{%- set auto_populated_fields = method_settings.auto_populated_fields if method_settings else [] -%}
+{%- set auto_populated_field_sample_value = "explicit value for autopopulate-able field" -%}
 {% with method_name = method.client_method_name|snake_case + "_unary" if method.extended_lro and not full_extended_lro else method.client_method_name|snake_case, method_output = method.extended_lro.operation_type if method.extended_lro and not full_extended_lro else method.output %}
 @pytest.mark.parametrize("request_type", [
-  {{ method.input.ident }},
-  dict,
+  {{ method.input.ident }}({
+    {% for auto_populated_field in auto_populated_fields %}
+    "{{ auto_populated_field }}": "{{ auto_populated_field_sample_value }}",
+    {% endfor %}
+  }),
+  {
+    {% for auto_populated_field in auto_populated_fields %}
+    "{{ auto_populated_field }}": "{{ auto_populated_field_sample_value }}",
+    {% endfor %}
+  },
 ])
 def test_{{ method_name }}(request_type, transport: str = 'grpc'):
-    {% with auto_populated_field_sample_value = "explicit value for autopopulate-able field" %}
     client = {{ service.client_name }}(
         credentials=ga_credentials.AnonymousCredentials(),
         transport=transport,
     )
 
     # Everything is optional in proto3 as far as the runtime is concerned,
     # and we are mocking out the actual API, so just send an empty request.
-    request = request_type()
-    {# Set UUID4 fields so that they are not automatically populated. #}
-    {% with method_settings = api.all_method_settings.get(method.meta.address.proto) %}
-    {% if method_settings is not none %}
-    {% for auto_populated_field in method_settings.auto_populated_fields %}
-    if isinstance(request, dict):
-        request['{{ auto_populated_field }}'] = "{{ auto_populated_field_sample_value }}"
-    else:
-        request.{{ auto_populated_field }} = "{{ auto_populated_field_sample_value }}"
-    {% endfor %}
-    {% endif %}{# if method_settings is not none #}
-    {% endwith %}{# method_settings #}
+    request = request_type
     {% if method.client_streaming %}
     requests = [request]
     {% endif %}
@@ -71,13 +70,9 @@ def test_{{ method_name }}(request_type, transport: str = 'grpc'):
         assert next(args[0]) == request
         {% else %}
         request = {{ method.input.ident }}()
-        {% with method_settings = api.all_method_settings.get(method.meta.address.proto) %}
-        {% if method_settings is not none %}
-        {% for auto_populated_field in method_settings.auto_populated_fields %}
+        {% for auto_populated_field in auto_populated_fields %}
         request.{{ auto_populated_field }} = "{{ auto_populated_field_sample_value }}"
         {% endfor %}
-        {% endif %}{# if method_settings is not none #}
-        {% endwith %}{# method_settings #}
         assert args[0] == request
         {% endif %}
 
@@ -118,10 +113,9 @@ def test_{{ method_name }}(request_type, transport: str = 'grpc'):
     {% endif %}{# end oneof/optional #}
     {% endfor %}
     {% endif %}
-    {% endwith %}{# auto_populated_field_sample_value #}
+    {%- if not method.client_streaming %}
 
 
-{% if not method.client_streaming %}
 def test_{{ method_name }}_non_empty_request_with_auto_populated_field():
     # This test is a coverage failsafe to make sure that UUID4 fields are
     # automatically populated, according to AIP-4235, with non-empty requests.
@@ -265,27 +259,27 @@ async def test_{{ method_name }}_async_use_cached_wrapped_rpc(transport: str = "
         assert mock_rpc.call_count == 2
 
 @pytest.mark.asyncio
-async def test_{{ method_name }}_async(transport: str = 'grpc_asyncio', request_type={{ method.input.ident }}):
-    {% with auto_populated_field_sample_value = "explicit value for autopopulate-able field" %}
+@pytest.mark.parametrize("request_type", [
+  {{ method.input.ident }}({
+    {%- for auto_populated_field in auto_populated_fields %}
+    "{{ auto_populated_field }}": "{{ auto_populated_field_sample_value }}",
+    {%- endfor %}
+  }),
+  {
+    {%- for auto_populated_field in auto_populated_fields %}
+    "{{ auto_populated_field }}": "{{ auto_populated_field_sample_value }}",
+    {%- endfor %}
+  },
+])
+async def test_{{ method_name }}_async(request_type, transport: str = 'grpc_asyncio'):
     client = {{ service.async_client_name }}(
         credentials=async_anonymous_credentials(),
         transport=transport,
     )
 
     # Everything is optional in proto3 as far as the runtime is concerned,
     # and we are mocking out the actual API, so just send an empty request.
-    request = request_type()
-    {# Set UUID4 fields so that they are not automatically populated. #}
-    {% with method_settings = api.all_method_settings.get(method.meta.address.proto) %}
-    {% if method_settings is not none %}
-    {% for auto_populated_field in method_settings.auto_populated_fields %}
-    if isinstance(request, dict):
-        request['{{ auto_populated_field }}'] = "{{ auto_populated_field_sample_value }}"
-    else:
-        request.{{ auto_populated_field }} = "{{ auto_populated_field_sample_value }}"
-    {% endfor %}
-    {% endif %}{# if method_settings is not none #}
-    {% endwith %}{# method_settings #}
+    request = request_type
     {% if method.client_streaming %}
     requests = [request]
     {% endif %}
@@ -335,13 +329,9 @@ async def test_{{ method_name }}_async(transport: str = 'grpc_asyncio', request_
         assert next(args[0]) == request
         {% else %}
         request = {{ method.input.ident }}()
-        {% with method_settings = api.all_method_settings.get(method.meta.address.proto) %}
-        {% if method_settings is not none %}
-        {% for auto_populated_field in method_settings.auto_populated_fields %}
+        {% for auto_populated_field in auto_populated_fields %}
         request.{{ auto_populated_field }} = "{{ auto_populated_field_sample_value }}"
         {% endfor %}
-        {% endif %}{# if method_settings is not none #}
-        {% endwith %}{# method_settings #}
         assert args[0] == request
         {% endif %}
 
@@ -378,12 +368,6 @@ async def test_{{ method_name }}_async(transport: str = 'grpc_asyncio', request_
     {% endif %}{# oneof/optional #}
     {% endfor %}
     {% endif %}
-    {% endwith %}{# auto_populated_field_sample_value #}
-
-
-@pytest.mark.asyncio
-async def test_{{ method_name }}_async_from_dict():
-    await test_{{ method_name }}_async(request_type=dict)
 {% endif %}{# full_extended_lro #}
 
 {% if method.field_headers and not method.client_streaming and not method.explicit_routing %}