feat: Make REST unit tests support numeric enums (#1423)

Support numeric enums in generated unit tests: default templates and Ads templates

Author: vchudnov-g

gapic/ads-templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2

@@ -1217,7 +1217,10 @@ def test_{{ method_name }}_rest_required_fields(request_type={{ method.input.ide
                     {{ req_field.type.python_type(req_field.field_pb.default_value or 0) }},
                     {% endif %}{# default is str #}
                 ),
-                {% endfor %}
+              {% endfor %}
+              {% if opts.rest_numeric_enums %}
+                ('$alt', 'json;enum-encoding=int')
+              {% endif %}
             ]
             actual_params = req.call_args.kwargs['params']
             assert expected_params == actual_params

gapic/templates/tests/unit/gapic/%name_%version/%sub/test_%service.py.j2

@@ -628,10 +628,10 @@ def test_{{ service.client_name|snake_case }}_create_channel_credentials_file(cl
 
 {% for method in service.methods.values() if 'rest' in opts.transport %}
 {% if method.extended_lro %}
-{{ test_macros.rest_required_tests(method, service, full_extended_lro=True) }}
+{{ test_macros.rest_required_tests(method, service, numeric_enums=opts.rest_numeric_enums, full_extended_lro=True) }}
 
 {% endif %}
-{{ test_macros.rest_required_tests(method, service) }}
+{{ test_macros.rest_required_tests(method, service, numeric_enums=opts.rest_numeric_enums) }}
 
 {% endfor -%} {#- method in methods for rest #}
 

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

@@ -833,7 +833,7 @@ def test_{{ method_name }}_raw_page_lro():
 {% endif %}{# method.paged_result_field #}{% endwith %}
 {% endmacro %}
 
-{% macro rest_required_tests(method, service, full_extended_lro=False) %}
+{% macro rest_required_tests(method, service, numeric_enums=False, full_extended_lro=False) %}
 {% with method_name = method.safe_name|snake_case + "_unary" if method.extended_lro and not full_extended_lro else method.name|snake_case, method_output = method.extended_lro.operation_type if method.extended_lro and not full_extended_lro else method.output %}{% if method.http_options %}
 {# TODO(kbandes): remove this if condition when lro and client streaming are supported. #}
 {% if not method.client_streaming %}
@@ -1076,7 +1076,10 @@ def test_{{ method_name }}_rest_required_fields(request_type={{ method.input.ide
                     {{ req_field.type.python_type(req_field.field_pb.default_value or 0) }},
                     {% endif %}{# default is str #}
                 ),
-                {% endfor %}
+              {% endfor %}
+              {% if numeric_enums %}
+                ('$alt', 'json;enum-encoding=int')
+              {% endif %}
             ]
             actual_params = req.call_args.kwargs['params']
             assert expected_params == actual_params