chore: use mock.ANY instead of None in empty request tests to cater for AIP-4235

Author: parthea

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

@@ -152,15 +152,20 @@ def test_{{ method_name }}_non_empty_request_with_auto_populated_field():
 {% for auto_populated_field in method_settings.auto_populated_fields %}
         # Ensure that the uuid4 field is set according to AIP 4235
         assert re.match(r"{{ get_uuid4_re() }}", args[0].{{ auto_populated_field }})
-        # clear UUID field so that the check below succeeds
-        args[0].{{ auto_populated_field }} = None
 {% endfor %}
 {% endif %}{# if method_settings is not none #}
 {% endwith %}{# method_settings #}
         assert args[0] == {{ method.input.ident }}(
         {% for field in method.input.fields.values() if field.ident|string() == "str" and not field.uuid4 %}
             {{ field.name }}={{ field.mock_value }},
         {% endfor %}
+{% 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 %}
+            {{ auto_populated_field }}=mock.ANY,
+{% endfor %}
+{% endif %}
+{% endwith %}
         )
 {% endif %}
 
@@ -1577,16 +1582,21 @@ def test_{{ method_name }}_rest_no_http_options():
         {% for auto_populated_field in method_settings.auto_populated_fields %}
         # Ensure that the uuid4 field is set according to AIP 4235
         assert re.match(r"{{ get_uuid4_re() }}", args[0].{{ auto_populated_field }})
-        # clear UUID field so that the check below succeeds
-        args[0].{{ auto_populated_field }} = None
         {% endfor %}{# for auto_populated_field in method_settings.auto_populated_fields #}
         {% endif %}{# if method_settings is not none #}
         {% endwith %}{# method_settings #}
         {% if request_dict %}
         request_msg = {{ method.input.ident }}(**{{ request_dict }})
         {% else %}
         request_msg = {{ method.input.ident }}()
-        {% endif %}{# request_dict #}      
+        {% endif %}{# request_dict #}
+        {% 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 %}
+        request_msg.{{ auto_populated_field }} = mock.ANY
+        {% endfor %}
+        {% endif %}
+        {% endwith %}
         assert args[0] == request_msg
 
         {% if routing_param %}