chore: test CommonResource resource name alias (googleapis#16965)

Add a test case for resource name alias functionality in
CommonResources. This is to support
googleapis#16945.

Author: ohmayr

packages/gapic-generator/tests/unit/schema/test_api.py

@@ -4499,3 +4499,33 @@ def test_method_settings_invalid_multiple_issues():
     assert re.match(".*squid.*not.*uuid4.*", error_yaml[method_example1][1].lower())
     assert re.match(".*octopus.*not.*uuid4.*", error_yaml[method_example1][2].lower())
     assert re.match(".*method.*not found.*", error_yaml[method_example2][0].lower())
+
+
+def test_file_level_resources_with_aliases():
+    """Proves that CLI aliases are passed down to file-level CommonResources."""
+    fdp = make_file_pb2(
+        name="nomenclature.proto",
+        package="nomenclature.linneaen.v1",
+        messages=(
+            make_message_pb2(
+                name="CreateSpeciesRequest",
+                fields=(make_field_pb2(name="species", number=1, type=9),),
+            ),
+        ),
+    )
+    res_pb2 = fdp.options.Extensions[resource_pb2.resource_definition]
+    resource_definition = res_pb2.add()
+    resource_definition.type = "nomenclature.linnaen.com/Species"
+    resource_definition.pattern.append("families/{family}/genera/{genus}/species/{species}")
+
+    # Pass down the resource-name-alias cli option
+    opts = Options.build("resource-name-alias=nomenclature.linnaen.com/Species:CustomSpecies")
+    
+    api_schema = api.API.build([fdp], package="nomenclature.linneaen.v1", opts=opts)
+    
+    # Trigger the property that evaluates the CommonResource
+    resource_msgs = api_schema.protos["nomenclature.proto"].resource_messages
+
+    # Verify that the resource exists with the overriden type
+    assert "nomenclature.linnaen.com/Species" in resource_msgs
+    assert resource_msgs["nomenclature.linnaen.com/Species"].resource_type == "CustomSpecies"