fix(rate-limiting): satisfy stricter test-lint and type-discipline gates picked up by rebase

The base branch added a stricter ruff config for tests (PT011/B017) and this
branch's own type-discipline gate flagged a mutable dict type annotation --
neither introduced by this branch's own changes, both surfaced by rebasing
onto a newer base. Narrowed the blind pytest.raises(Exception/ValueError)
assertions to ValidationError with a match on the actual validator message,
and annotated a Redis read-only result as Mapping instead of dict.

litellm/proxy/hooks/tag_rate_limiter.py

@@ -1151,10 +1151,11 @@ class _PROXY_TagRateLimiter(  # pyright: ignore[reportUnusedClass]  # only refer
                 # bypassing that in-memory layer, is the only way this
                 # read-then-later-increment split stays coherent.
                 # not `Final`: rebound each loop iteration, which basedpyright's
-                # LIT010/Final-in-loop check forbids; explicitly typed since
+                # LIT010/Final-in-loop check forbids; explicitly typed (as the
+                # read-only supertype, since this is never mutated) since
                 # RedisCache.async_batch_get_cache's own signature returns a
                 # bare, unparameterized dict
-                redis_values: dict[str, object] = await redis_cache.async_batch_get_cache(
+                redis_values: Mapping[str, object] = await redis_cache.async_batch_get_cache(
                     key_list=keys, parent_otel_span=parent_otel_span
                 )
                 resolved = [redis_values.get(key) for key in keys]  # mutable-ok: needs a real list

tests/test_litellm/proxy/hooks/test_tag_rate_limiter.py

@@ -12,6 +12,7 @@ from types import SimpleNamespace
 from typing import Final
 
 import pytest
+from pydantic import ValidationError
 
 import litellm
 from litellm.caching.dual_cache import DualCache
@@ -239,12 +240,12 @@ def test_extract_team_id_ignores_a_forged_value_in_the_non_authoritative_field()
 
 
 def test_tag_rate_limit_entry_rejects_zero_period_seconds():
-    with pytest.raises(Exception):
+    with pytest.raises(ValidationError, match="period_seconds must be a positive integer"):
         TagRateLimitEntry(name="n", limit=1, period_seconds=0)
 
 
 def test_tag_rate_limit_entry_rejects_negative_period_seconds():
-    with pytest.raises(Exception):
+    with pytest.raises(ValidationError, match="period_seconds must be a positive integer"):
         TagRateLimitEntry(name="n", limit=1, period_seconds=-1)
 
 
@@ -3409,7 +3410,7 @@ def test_ttl_for_concurrency_never_drops_below_the_safety_floor_even_with_a_lowe
 
 
 def test_tag_rate_limit_entry_rejects_non_positive_key_ttl_seconds():
-    with pytest.raises(ValueError):
+    with pytest.raises(ValidationError, match="key_ttl_seconds must be a positive integer"):
         TagRateLimitEntry(name="per_minute", limit=1, period_seconds=60, key_ttl_seconds=0)
 
 
@@ -3420,7 +3421,7 @@ def test_tag_rate_limit_entry_rejects_key_ttl_seconds_shorter_than_period_second
     resetting the counter to zero mid-window and letting tagged traffic
     exceed the configured limit.
     """
-    with pytest.raises(ValueError):
+    with pytest.raises(ValidationError, match="key_ttl_seconds must be at least period_seconds"):
         TagRateLimitEntry(name="per_minute", limit=1, period_seconds=60, key_ttl_seconds=59)
 
 
@@ -3430,7 +3431,7 @@ def test_tag_rate_limit_entry_rejects_key_ttl_seconds_shorter_than_period_second
 
 
 def test_tag_rate_limit_entry_rejects_non_positive_max_in_memory_cache_size():
-    with pytest.raises(ValueError):
+    with pytest.raises(ValidationError, match="max_in_memory_cache_size must be a positive integer"):
         TagRateLimitEntry(name="per_minute", limit=1, period_seconds=60, max_in_memory_cache_size=0)