Intercept httpx2 in the Microsoft Bot's Anthropic endpoint test (#761)

anthropic 1.x sends through httpx2 rather than httpx. The test patched
httpx.AsyncHTTPTransport, so with the newest SDK its request reached the
real Anthropic API and failed with 401, breaking main's CI. It now patches
httpx2.AsyncHTTPTransport, as the AG2 Bot's tests already do.

Author: davidmckayv

agent-microsoft/tests/test_main.py

@@ -191,11 +191,13 @@ async def respond(transport, request):
         seen.append(
             (request.url.scheme, request.url.host, request.url.path, request.headers.get("x-api-key"))
         )
-        async with httpx.ASGITransport(app=provider_app) as local_provider:
+        async with httpx2.ASGITransport(app=provider_app) as local_provider:
             return await local_provider.handle_async_request(request)
 
-    # Keep the real framework and Anthropic clients; replace only the network transport.
-    monkeypatch.setattr(httpx.AsyncHTTPTransport, "handle_async_request", respond)
+    # Keep the real framework and Anthropic clients; replace only the network transport. The
+    # Anthropic SDK sends through httpx2 (pydantic's fork) since 1.x, not httpx, so that is the
+    # transport to intercept; patching httpx here lets the request reach the real API.
+    monkeypatch.setattr(httpx2.AsyncHTTPTransport, "handle_async_request", respond)
     monkeypatch.setenv("MANAGED_AGENT_TOKEN", TOKEN)
     monkeypatch.setenv("BOT_PROVIDER", "anthropic")
     monkeypatch.setenv("BOT_MODEL", "claude-sonnet-4-5")