From 869a5df8cc7f43b2423e5a41940e95c2a86a1be5 Mon Sep 17 00:00:00 2001
From: Deepanshu Pal <40927968+DeepanshuPal@users.noreply.github.com>
Date: Fri, 2 Oct 2026 06:43:04 +0530
Subject: [PATCH] test(proxy): move in-band error tests into the existing
 streaming handler test file

---
 .../test_streaming_handler.py                 | 70 ++++++++++++++++++-
 1 file changed, 69 insertions(+), 1 deletion(-)

diff --git a/tests/unit/proxy/pass_through_endpoints/test_streaming_handler.py b/tests/unit/proxy/pass_through_endpoints/test_streaming_handler.py
index 9d4532df49a..897c951c482 100644
--- a/tests/unit/proxy/pass_through_endpoints/test_streaming_handler.py
+++ b/tests/unit/proxy/pass_through_endpoints/test_streaming_handler.py
@@ -1,7 +1,7 @@
 import json
 from collections.abc import Iterator
 from datetime import datetime
-from unittest.mock import MagicMock
+from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 
@@ -230,3 +230,71 @@ async def test_failed_anthropic_stream_records_partial_usage_off_the_event_loop(
     partial_usage = logging_obj.record_partial_usage_for_failure.call_args.kwargs["usage"]
     assert partial_usage.completion_tokens > 100_000
     assert_loop_stayed_free(took, lags)
+
+
+CLAUDE_MODEL = "claude-fable-5"
+
+
+def _anthropic_error_frame(error_type: str, message: str) -> bytes:
+    payload = {"type": "error", "error": {"type": error_type, "message": message}}
+    return f"event: error\ndata: {json.dumps(payload)}\n\n".encode()
+
+
+def _anthropic_error_logging_obj() -> MagicMock:
+    logging_obj = MagicMock(spec=LiteLLMLoggingObj)
+    logging_obj.model_call_details = {"model": CLAUDE_MODEL, "stream": True}
+    logging_obj.optional_params = {}
+    logging_obj.litellm_params = {}
+    logging_obj.litellm_call_id = "test-call-id"
+    logging_obj.get_router_model_id.return_value = None
+    logging_obj.dispatch_success_handlers = AsyncMock()
+    logging_obj.dispatch_failure_handlers = AsyncMock()
+    return logging_obj
+
+
+async def _route_anthropic_stream(logging_obj: MagicMock, raw_bytes: list[bytes]) -> None:
+    await PassThroughStreamingHandler._route_streaming_logging_to_handler(
+        litellm_logging_obj=logging_obj,
+        passthrough_success_handler_obj=PassThroughEndpointLogging(),
+        url_route="/anthropic/v1/messages",
+        request_body={"model": CLAUDE_MODEL, "stream": True},
+        endpoint_type=EndpointType.ANTHROPIC,
+        start_time=datetime.now(),
+        raw_bytes=raw_bytes,
+        end_time=datetime.now(),
+        model=CLAUDE_MODEL,
+    )
+    await GLOBAL_LOGGING_WORKER.flush()
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "error_type, expected_status",
+    [("api_error", 500), ("overloaded_error", 503), ("rate_limit_error", 429)],
+)
+async def test_in_band_error_frame_is_logged_as_failure_not_success(error_type: str, expected_status: int):
+    logging_obj = _anthropic_error_logging_obj()
+
+    await _route_anthropic_stream(
+        logging_obj,
+        [*_interrupted_anthropic_stream(CLAUDE_MODEL, "partial answer"), _anthropic_error_frame(error_type, "boom")],
+    )
+
+    logging_obj.dispatch_success_handlers.assert_not_awaited()
+    logging_obj.dispatch_failure_handlers.assert_awaited_once()
+    exception = logging_obj.dispatch_failure_handlers.await_args.args[0]
+    assert exception.status_code == expected_status
+    assert "boom" in str(exception)
+    partial_usage = logging_obj.record_partial_usage_for_failure.call_args.kwargs["usage"]
+    assert partial_usage.prompt_tokens == 29
+    assert partial_usage.completion_tokens > 0
+
+
+@pytest.mark.asyncio
+async def test_stream_without_error_frame_still_logs_success():
+    logging_obj = _anthropic_error_logging_obj()
+
+    await _route_anthropic_stream(logging_obj, _interrupted_anthropic_stream(CLAUDE_MODEL, "partial answer"))
+
+    logging_obj.dispatch_success_handlers.assert_awaited_once()
+    logging_obj.dispatch_failure_handlers.assert_not_awaited()