microsoft · Rodrigo Brandão (rodrigobr-msft) · Sep 25, 2026 · Sep 24, 2026 · Sep 24, 2026 · Sep 24, 2026
@@ -75,7 +75,6 @@ def _create_scenario() -> AiohttpScenario:
     app = AgentApplication[TurnState](
         options=ApplicationOptions(
             storage=storage,
-            adapter=adapter,
             proactive=ProactiveOptions(),
         ),
         authorization=authorization,

@@ -83,6 +83,25 @@ client to interact with the agent. Auth credentials and general SDK config setti
 
 Swap one for the other and your assertions stay the same.
 
+### Existing AgentApplication
+
+Use `AiohttpScenario.from_app(...)` when the `AgentApplication` is already
+constructed. Pass the application's existing `CloudAdapter` to preserve its
+middleware, host validation, client factories, and error handling:
+
+```python
+scenario = AiohttpScenario.from_app(
+    AGENT_APP,
+    adapter=ADAPTER,
+    use_jwt_middleware=False,
+)
+```
+
+All arguments after `AGENT_APP` are keyword-only. If `adapter` is omitted, the
+scenario creates a default `CloudAdapter` from `AGENT_APP.connection_manager`.
+The generated adapter does not inherit configuration from another adapter used
+to host the application.
+
 ## AgentClient
 
 The client you get from a scenario. Send messages, collect replies, make

@@ -74,6 +74,42 @@ async with scenario.run() as factory:
     )))
 ```
 
+Use `from_app(...)` when the `AgentApplication` already exists:
+
+```python
+AiohttpScenario.from_app(
+    app: AgentApplication,
+    *,
+    adapter: CloudAdapter | None = None,
+    config: ScenarioConfig | None = None,
+    use_jwt_middleware: bool = True,
+    sdk_config: dict | None = None,
+)
+```
+
+All arguments after `app` are keyword-only.
+
+| Parameter | Type | Default | Description |
+|-----------|------|---------|-------------|
+| `app` | `AgentApplication` | *(required)* | Existing agent application to host |
+| `adapter` | `CloudAdapter \| None` | `None` | Adapter used to host the application; when omitted, one is created from `app.connection_manager` |
+| `config` | `ScenarioConfig \| None` | `None` | Scenario-level settings (ports, env file, etc.) |
+| `use_jwt_middleware` | `bool` | `True` | Enable JWT auth middleware |
+| `sdk_config` | `dict \| None` | `None` | SDK configuration used for client authentication |
+
+```python
+scenario = AiohttpScenario.from_app(
+    AGENT_APP,
+    adapter=ADAPTER,
+    use_jwt_middleware=False,
+)
+```
+
+Pass the application's production adapter when the test must preserve adapter
+middleware, host validation, client factories, or error handling. The default
+adapter only reuses the application's connection manager and does not inherit
+configuration from another adapter used to host the application.
+
 ### ActivityHandlerScenario
 
 ```python

@@ -83,6 +83,25 @@ client to interact with the agent. Auth credentials and general SDK config setti
 
 Swap one for the other and your assertions stay the same.
 
+### Existing AgentApplication
+
+Use `AiohttpScenario.from_app(...)` when the `AgentApplication` is already
+constructed. Pass the application's existing `CloudAdapter` to preserve its
+middleware, host validation, client factories, and error handling:
+
+```python
+scenario = AiohttpScenario.from_app(
+    AGENT_APP,
+    adapter=ADAPTER,
+    use_jwt_middleware=False,
+)
+```
+
+All arguments after `AGENT_APP` are keyword-only. If `adapter` is omitted, the
+scenario creates a default `CloudAdapter` from `AGENT_APP.connection_manager`.
+The generated adapter does not inherit configuration from another adapter used
+to host the application.
+
 ## AgentClient
 
 The client you get from a scenario. Send messages, collect replies, make

@@ -9,9 +9,12 @@
 web server.
 
 Use :meth:`AiohttpScenario.from_app` when a sample or test already defines
-module-level AgentApplication components, and use :meth:`AiohttpScenario.create`
-when the test wants the scenario to create the standard storage, adapter,
-authorization, and connection components before registering handlers.
+module-level AgentApplication components. Pass its hosting ``CloudAdapter`` to
+preserve production adapter configuration, or omit it to create a default
+adapter from the application's connection manager. Use
+:meth:`AiohttpScenario.create` when the test wants the scenario to create the
+standard storage, adapter, authorization, and connection components before
+registering handlers.
 """
 
 from __future__ import annotations
@@ -56,6 +59,7 @@
 
 logger = logging.getLogger(__name__)
 
+
 @dataclass(frozen=True)
 class AgentEnvironment:
     """Components used by an in-process AgentApplication scenario.
@@ -80,6 +84,7 @@ class AgentEnvironment:
     storage: Storage
     connections: Connections
 
+
 class AiohttpScenario(Scenario):
     """Scenario that hosts an AgentApplication in-process using aiohttp.
 
@@ -93,11 +98,17 @@ class AiohttpScenario(Scenario):
     - :meth:`create` builds a standard environment and then calls a setup
       function to register routes/handlers.
     - :meth:`from_app` wraps an existing AgentApplication, such as one defined
-      at module scope in a sample's ``agents.py`` file.
+      at module scope in a sample's ``agents.py`` file. It accepts the
+      application's CloudAdapter or creates a default adapter from the
+      application's connection manager.
 
     Example::
 
-        scenario = AiohttpScenario.from_app(AGENT_APP, use_jwt_middleware=False)
+        scenario = AiohttpScenario.from_app(
+            AGENT_APP,
+            adapter=ADAPTER,
+            use_jwt_middleware=False,
+        )
 
         async with scenario.client() as client:
             await client.send("Hello!", wait=0.2)
@@ -178,8 +189,10 @@ def _default_env_factory(
         factory when no custom environment factory is provided.
         """
         env_vars = dotenv_values(config.env_file_path or ".env")
-        sdk_config = load_configuration_from_env(env_vars) if sdk_config is None else sdk_config
-
+        sdk_config = (
+            load_configuration_from_env(env_vars) if sdk_config is None else sdk_config
+        )
+
         connection_manager: Connections
         if omit_connections:
             connection_manager = ConnectionManager(
@@ -188,7 +201,7 @@ def _default_env_factory(
                     "SERVICE_CONNECTION": AgentAuthConfiguration(
                         anonymous_allowed=True,
                     )
-                }
+                },
             )
         else:
             connection_manager = MsalConnectionManager(**sdk_config)
@@ -197,7 +210,7 @@ def _default_env_factory(
         adapter = CloudAdapter(connection_manager=connection_manager)
         authorization = Authorization(storage, connection_manager, **sdk_config)
         agent_application = AgentApplication[TurnState](
-            storage=storage, adapter=adapter, authorization=authorization, **sdk_config
+            storage=storage, authorization=authorization, **sdk_config
         )
 
         return AgentEnvironment(
@@ -250,17 +263,19 @@ def _env_factory() -> AgentEnvironment:
             return AiohttpScenario._default_env_factory(
                 config=config, sdk_config=sdk_config, omit_connections=omit_connections
             )
-        
+
         return AiohttpScenario(
             setup,
             config,
             use_jwt_middleware=use_jwt_middleware,
             env_factory=_env_factory,
         )
-    
+
     @staticmethod
     def from_app(
         app: AgentApplication,
+        *,
+        adapter: CloudAdapter | None = None,
         config: ScenarioConfig | None = None,
         use_jwt_middleware: bool = True,
         sdk_config: dict | None = None,
@@ -269,10 +284,15 @@ def from_app(
 
         Use this factory for sample-style modules that already define
         AgentApplication and supporting components at module scope. The scenario
-        hosts the provided application through its configured adapter and exposes
-        the resulting environment for fixtures and inspection.
+        hosts the provided application through the supplied adapter and exposes
+        the resulting environment for fixtures and inspection. When ``adapter``
+        is omitted, a default CloudAdapter is created from the application's
+        connection manager. Pass the production adapter when tests need its
+        middleware, host validation, client factories, or error handling.
 
         :param app: AgentApplication instance to host.
+        :param adapter: Optional CloudAdapter used to host the application.
+            When omitted, one is created from ``app.connection_manager``.
         :param config: Optional scenario configuration.
         :param use_jwt_middleware: Whether to enable JWT middleware on the
             aiohttp route.
@@ -286,11 +306,13 @@ def from_app(
         if storage is None:
             raise AttributeError("AgentApplication storage could not be resolved.")
 
+        adapter = adapter or CloudAdapter(connection_manager=app.connection_manager)
+
         env = AgentEnvironment(
             config=sdk_config or {},
             agent_application=app,
             authorization=app.auth,
-            adapter=app.adapter,
+            adapter=adapter,
             storage=cast(Storage, storage),
             connections=app.connection_manager,
         )

@@ -30,7 +30,7 @@
 AUTHORIZATION = Authorization(STORAGE, CONNECTION_MANAGER, **agents_sdk_config)
 
 AGENT_APP = AgentApplication[TurnState](
-    storage=STORAGE, adapter=ADAPTER, authorization=AUTHORIZATION, **agents_sdk_config
+    storage=STORAGE, authorization=AUTHORIZATION, **agents_sdk_config
 )
 
 
@@ -55,6 +55,7 @@ async def on_message(context: TurnContext, _):
     try:
         start_server(
             agent_application=AGENT_APP,
+            adapter=ADAPTER,
             auth_configuration=CONNECTION_MANAGER.get_default_connection_configuration(),
         )
     except Exception as error:

@@ -9,7 +9,9 @@
 
 
 def start_server(
-    agent_application: AgentApplication, auth_configuration: AgentAuthConfiguration
+    agent_application: AgentApplication,
+    adapter: CloudAdapter,
+    auth_configuration: AgentAuthConfiguration,
 ):
     async def entry_point(req: Request) -> Response:
         agent: AgentApplication = req.app["agent_app"]
@@ -25,7 +27,7 @@ async def entry_point(req: Request) -> Response:
     APP.router.add_get("/api/messages", lambda _: Response(status=200))
     APP["agent_configuration"] = auth_configuration
     APP["agent_app"] = agent_application
-    APP["adapter"] = agent_application.adapter
+    APP["adapter"] = adapter
 
     try:
         run_app(APP, host="localhost", port=environ.get("PORT", 3978))

@@ -5,9 +5,40 @@
 
 import pytest
 
-from microsoft_agents.hosting.testing.aiohttp_scenario import AiohttpScenario, AgentEnvironment
+from microsoft_agents.hosting.aiohttp import CloudAdapter
+from microsoft_agents.hosting.core import (
+    AgentApplication,
+    AgentAuthConfiguration,
+    AnonymousTokenProvider,
+    Authorization,
+    ConnectionManager,
+    MemoryStorage,
+    TurnState,
+)
+from microsoft_agents.hosting.testing import aiohttp_scenario
+from microsoft_agents.hosting.testing.aiohttp_scenario import (
+    AiohttpScenario,
+    AgentEnvironment,
+)
 from microsoft_agents.hosting.testing.core import Scenario, ScenarioConfig
 
+
+def _create_agent_application():
+    connections = ConnectionManager(
+        provider_factory=lambda _: AnonymousTokenProvider(),
+        connections_configurations={
+            "SERVICE_CONNECTION": AgentAuthConfiguration(anonymous_allowed=True)
+        },
+    )
+    storage = MemoryStorage()
+    authorization = Authorization(storage, connections)
+    app = AgentApplication[TurnState](
+        storage=storage,
+        authorization=authorization,
+    )
+    return app, connections
+
+
 # ============================================================================
 # AgentEnvironment Tests
 # ============================================================================
@@ -137,6 +168,47 @@ def init_agent(env: AgentEnvironment) -> None:
         assert scenario._env is None
 
 
+# ============================================================================
+# AiohttpScenario Existing Application Tests
+# ============================================================================
+
+
+class TestAiohttpScenarioFromApp:
+    """Tests for constructing a scenario from an existing application."""
+
+    def test_uses_provided_adapter(self):
+        """from_app preserves an explicitly supplied CloudAdapter."""
+        app, connections = _create_agent_application()
+        adapter = CloudAdapter(connection_manager=connections)
+
+        scenario = AiohttpScenario.from_app(app, adapter=adapter)
+
+        assert scenario.agent_environment.adapter is adapter
+
+    def test_creates_adapter_from_application_connection_manager(self, monkeypatch):
+        """from_app creates a default adapter from the application's connections."""
+        app, connections = _create_agent_application()
+        created_adapter = object()
+
+        def create_adapter(*, connection_manager):
+            assert connection_manager is connections
+            return created_adapter
+
+        monkeypatch.setattr(aiohttp_scenario, "CloudAdapter", create_adapter)
+
+        scenario = AiohttpScenario.from_app(app)
+
+        assert scenario.agent_environment.adapter is created_adapter
+        assert scenario.agent_environment.connections is connections
+
+    def test_optional_arguments_are_keyword_only(self):
+        """from_app rejects positional optional arguments."""
+        app, _ = _create_agent_application()
+
+        with pytest.raises(TypeError):
+            AiohttpScenario.from_app(app, ScenarioConfig())
+
+
 # ============================================================================
 # AiohttpScenario Configuration Tests
 # ============================================================================

@@ -187,7 +187,7 @@ ADAPTER = CloudAdapter(connection_manager=CONNECTION_MANAGER)
 AUTHORIZATION = Authorization(STORAGE, CONNECTION_MANAGER, **agents_sdk_config)
 
 AGENT_APP = AgentApplication[TurnState](
-    storage=STORAGE, adapter=ADAPTER, authorization=AUTHORIZATION, **agents_sdk_config
+    storage=STORAGE, authorization=AUTHORIZATION, **agents_sdk_config
 )
 
 @AGENT_APP.activity("message")
@@ -198,6 +198,7 @@ async def on_message(context: TurnContext, state: TurnState):
 
 start_server(
     agent_application=AGENT_APP,
+    adapter=ADAPTER,
     auth_configuration=CONNECTION_MANAGER.get_default_connection_configuration(),
 )
 ```