[python] Add mock API tests for service/multiple-services and fix generator duplicate class name bug

.chronus/changes/service-multiple-services-test-2026-4-13-23-17-38.md

@@ -0,0 +1,7 @@
+---
+changeKind: internal
+packages:
+  - "@typespec/http-client-python"
+---
+
+Add mock API tests for `service/multiple-services` Spector scenario, covering `ServiceAClient` and `ServiceBClient` with separate versioned operation groups. Fix Python code generator to merge operation groups with the same class name across multiple clients in the same namespace, avoiding duplicate class definitions.

packages/http-client-python/eng/scripts/ci/regenerate-common.ts

@@ -3,7 +3,7 @@ import { dirname, join, relative, resolve } from "path";
 
 // ---- Shared constants ----
 
-export const SKIP_SPECS: string[] = ["type/file", "service/multiple-services"];
+export const SKIP_SPECS: string[] = ["type/file"];
 
 export const SpecialFlags: Record<string, Record<string, any>> = {
   azure: {
@@ -135,6 +135,10 @@ export const BASE_AZURE_EMITTER_OPTIONS: Record<
   "service/multi-service": {
     namespace: "service.multiservice",
   },
+  "service/multiple-services": {
+    "package-name": "service-multiple-services",
+    namespace: "service.multipleservices",
+  },
 };
 
 export const BASE_EMITTER_OPTIONS: Record<

packages/http-client-python/generator/pygen/codegen/serializers/__init__.py

@@ -353,11 +353,27 @@ def _serialize_and_write_operations_folder(
     ) -> None:
         operations_folder_name = self.code_model.operations_folder_name(namespace)
         generation_path = self.code_model.get_generation_dir(namespace)
+
+        # Deduplicate operation groups with the same class_name by merging their operations.
+        # This handles the case where multiple clients share operation group names in the same namespace
+        # (e.g., both ServiceA and ServiceB have an "Operations" interface).
+        seen_class_names: dict[str, OperationGroup] = {}
+        class_operation_groups: list[OperationGroup] = []
+        for og in operation_groups:
+            if og.class_name in seen_class_names:
+                seen_class_names[og.class_name].operations.extend(og.operations)
+            else:
+                seen_class_names[og.class_name] = og
+                class_operation_groups.append(og)
+
         for async_mode, async_path in self.serialize_loop:
             prefix_path = f"{async_path}{operations_folder_name}"
-            # write init file
+            # write init file (use deduplicated list to avoid duplicate imports)
             operations_init_serializer = OperationsInitSerializer(
-                code_model=self.code_model, operation_groups=operation_groups, env=env, async_mode=async_mode
+                code_model=self.code_model,
+                operation_groups=class_operation_groups,
+                env=env,
+                async_mode=async_mode,
             )
             self.write_file(
                 generation_path / Path(f"{prefix_path}/__init__.py"),
@@ -367,16 +383,21 @@ def _serialize_and_write_operations_folder(
             # write operations file
             OgLoop = namedtuple("OgLoop", ["operation_groups", "filename"])
             if self.code_model.options["combine-operation-files"]:
+                # Pass all operation_groups for request builder generation, but class_operation_groups
+                # for class definitions to avoid duplicate class names in the output.
                 loops = [OgLoop(operation_groups, "_operations")]
             else:
-                loops = [OgLoop([og], og.filename) for og in operation_groups]
+                loops = [OgLoop([og], og.filename) for og in class_operation_groups]
             for ogs, filename in loops:
                 operation_group_serializer = OperationGroupsSerializer(
                     code_model=self.code_model,
                     operation_groups=ogs,
                     env=env,
                     async_mode=async_mode,
                     client_namespace=namespace,
+                    class_operation_groups=class_operation_groups
+                    if self.code_model.options["combine-operation-files"]
+                    else None,
                 )
                 self.write_file(
                     generation_path / Path(f"{prefix_path}/{filename}.py"),

packages/http-client-python/generator/pygen/codegen/serializers/operation_groups_serializer.py

@@ -32,9 +32,11 @@ def __init__(
         async_mode: bool,
         *,
         client_namespace: Optional[str] = None,
+        class_operation_groups: Optional[list[OperationGroup]] = None,
     ):
         super().__init__(code_model, env, async_mode, client_namespace=client_namespace)
         self.operation_groups = operation_groups
+        self.class_operation_groups = class_operation_groups if class_operation_groups is not None else operation_groups
         self.async_mode = async_mode
 
     def _get_request_builders(
@@ -77,6 +79,7 @@ def serialize(self) -> str:
         return template.render(
             code_model=self.code_model,
             operation_groups=self.operation_groups,
+            class_operation_groups=self.class_operation_groups,
             imports=FileImportSerializer(
                 imports,
                 async_mode=self.async_mode,

packages/http-client-python/generator/pygen/codegen/templates/operation_groups_container.py.jinja2

@@ -17,6 +17,6 @@
         {% endfor %}
     {% endfor %}
 {% endif %}
-{% for operation_group in operation_groups %}
+{% for operation_group in class_operation_groups %}
     {% include "operation_group.py.jinja2" %}
 {% endfor %}

packages/http-client-python/tests/mock_api/azure/asynctests/test_service_multiple_services_async.py

@@ -0,0 +1,55 @@
+# -------------------------------------------------------------------------
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See License.txt in the project root for
+# license information.
+# --------------------------------------------------------------------------
+import pytest
+from azure.core.exceptions import HttpResponseError
+from service.multipleservices.aio import ServiceAClient, ServiceBClient
+from service.multipleservices.models import VersionsA, VersionsB
+
+
+@pytest.fixture
+def client_a():
+    return ServiceAClient(endpoint="http://localhost:3000")
+
+
+@pytest.fixture
+def client_b():
+    return ServiceBClient(endpoint="http://localhost:3000")
+
+
+@pytest.mark.asyncio
+async def test_service_multiple_services_service_a_operations(client_a):
+    with pytest.raises(HttpResponseError):
+        async with ServiceAClient(endpoint="http://localhost:3000", api_version=VersionsA.AV1) as wrong_client:
+            await wrong_client.operations.op_a()
+
+    await client_a.operations.op_a()
+
+
+@pytest.mark.asyncio
+async def test_service_multiple_services_service_a_sub_namespace(client_a):
+    with pytest.raises(HttpResponseError):
+        async with ServiceAClient(endpoint="http://localhost:3000", api_version=VersionsA.AV1) as wrong_client:
+            await wrong_client.sub_namespace.sub_op_a()
+
+    await client_a.sub_namespace.sub_op_a()
+
+
+@pytest.mark.asyncio
+async def test_service_multiple_services_service_b_operations(client_b):
+    with pytest.raises(HttpResponseError):
+        async with ServiceBClient(endpoint="http://localhost:3000", api_version=VersionsB.BV1) as wrong_client:
+            await wrong_client.operations.op_b()
+
+    await client_b.operations.op_b()
+
+
+@pytest.mark.asyncio
+async def test_service_multiple_services_service_b_sub_namespace(client_b):
+    with pytest.raises(HttpResponseError):
+        async with ServiceBClient(endpoint="http://localhost:3000", api_version=VersionsB.BV1) as wrong_client:
+            await wrong_client.sub_namespace.sub_op_b()
+
+    await client_b.sub_namespace.sub_op_b()

packages/http-client-python/tests/mock_api/azure/test_service_multiple_services.py

@@ -0,0 +1,53 @@
+# -------------------------------------------------------------------------
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See License.txt in the project root for
+# license information.
+# --------------------------------------------------------------------------
+import pytest
+from azure.core.exceptions import HttpResponseError
+from service.multipleservices import ServiceAClient, ServiceBClient
+from service.multipleservices.models import VersionsA, VersionsB
+
+
+@pytest.fixture
+def client_a():
+    with ServiceAClient(endpoint="http://localhost:3000") as client:
+        yield client
+
+
+@pytest.fixture
+def client_b():
+    with ServiceBClient(endpoint="http://localhost:3000") as client:
+        yield client
+
+
+def test_service_multiple_services_service_a_operations(client_a):
+    with pytest.raises(HttpResponseError):
+        with ServiceAClient(endpoint="http://localhost:3000", api_version=VersionsA.AV1) as wrong_client:
+            wrong_client.operations.op_a()
+
+    client_a.operations.op_a()
+
+
+def test_service_multiple_services_service_a_sub_namespace(client_a):
+    with pytest.raises(HttpResponseError):
+        with ServiceAClient(endpoint="http://localhost:3000", api_version=VersionsA.AV1) as wrong_client:
+            wrong_client.sub_namespace.sub_op_a()
+
+    client_a.sub_namespace.sub_op_a()
+
+
+def test_service_multiple_services_service_b_operations(client_b):
+    with pytest.raises(HttpResponseError):
+        with ServiceBClient(endpoint="http://localhost:3000", api_version=VersionsB.BV1) as wrong_client:
+            wrong_client.operations.op_b()
+
+    client_b.operations.op_b()
+
+
+def test_service_multiple_services_service_b_sub_namespace(client_b):
+    with pytest.raises(HttpResponseError):
+        with ServiceBClient(endpoint="http://localhost:3000", api_version=VersionsB.BV1) as wrong_client:
+            wrong_client.sub_namespace.sub_op_b()
+
+    client_b.sub_namespace.sub_op_b()