test(guardrails): mark the Azure capture lists as callee-filled

The request, thread and scope logs the new Azure tests capture are
accumulators a callback fills, which the no-mutation convention asks to
be marked rather than left bare. Mark all three with a reason, and hand
the captured requests back as a Sequence so a test cannot append to the
fixture's own log

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/test_litellm/proxy/guardrails/guardrail_hooks/azure/conftest.py

@@ -1,3 +1,4 @@
+from collections.abc import Sequence
 from typing import Final
 
 import httpx
@@ -31,9 +32,9 @@ def api_base() -> str:
 
 
 @pytest.fixture
-def capturing_handler() -> tuple[AsyncHTTPHandler, list[httpx.Request]]:
+def capturing_handler() -> tuple[AsyncHTTPHandler, Sequence[httpx.Request]]:
     """An HTTP handler answering every Content Safety call, paired with the requests it saw."""
-    sent: Final[list[httpx.Request]] = []
+    sent: Final[list[httpx.Request]] = []  # mutable-ok: callee-filled request log, handed back read-only
 
     def _record(request: httpx.Request) -> httpx.Response:
         sent.append(request)

tests/test_litellm/proxy/guardrails/guardrail_hooks/azure/test_azure_base.py

@@ -129,7 +129,7 @@ async def test_token_minting_failure_keeps_credential_detail_out_of_the_error(ap
 async def test_token_is_minted_off_the_event_loop_thread(api_base, capturing_handler):
     """Credential sources block: IMDS probes time out and the az CLI credential spawns a subprocess."""
     handler, _ = capturing_handler
-    minting_threads: Final[list[int]] = []
+    minting_threads: Final[list[int]] = []  # mutable-ok: callee-filled thread log
 
     def _record_thread() -> str:
         minting_threads.append(threading.get_ident())
@@ -150,7 +150,7 @@ async def test_token_is_minted_off_the_event_loop_thread(api_base, capturing_han
 
 def test_default_credential_is_built_once_per_process(monkeypatch):
     """Rebuilding it per request costs a fresh credential and token round trip on every scan."""
-    builds: Final[list[str]] = []
+    builds: Final[list[str]] = []  # mutable-ok: callee-filled scope log
 
     def _build(azure_scope: str):
         builds.append(azure_scope)