18 tests over local stub servers — no GPU, no weights, no network:
worker service_url health enforcement, the mux service + RemoteMuxEngine
(streaming, stats, mid-stream cancel, error propagation, dead service),
remote GGUF text models (routing, /v1 normalisation, auth, chat, SSE,
no-local-weights), RunPod engine selection (HF->vLLM, GGUF->llama.cpp,
pins, the missing-hf_gguf error), and the gateway (transparency when
nothing is remote, capability and per-model routing, verbatim multipart
forwarding, chat exclusion, clean 502).

Also stop the mux service dumping a broken-pipe traceback when a client
cancels a stream — hanging up IS the cancel signal there.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0182DhR1eFNPQyGmDrpHbedY