intelligence-router/tests/test_router_fallback_lxc.py

"""Tests for LXC fallback chain — Issue #7.

Full fallback: Main PC → OpenRouter → LXC. 503 when all backends down.
Uses conftest.py patches for URL mocking.
"""
import asyncio
import pytest
from httpx import Response, ASGITransport, AsyncClient
import respx

import main


class TestFallbackChain:
    """Tests for the full fallback chain."""

    def test_openrouter_failure_triggers_lxc(self):
        """When OpenRouter fails with network error, router falls back to LXC."""
        async def run_test():
            with respx.mock:
                # Sidecar is down — triggers fallback chain
                respx.get("http://localhost:8080/models/status").mock(
                    return_value=Response(503, json={"status": "error", "message": "not ready"})
                )
                # OpenRouter fails with network error
                respx.post("https://openrouter.ai/v1/chat/completions").mock(
                    side_effect=Exception("Connection refused")
                )
                # LXC health check passes
                respx.get("http://localhost:9999/v1/models").mock(
                    return_value=Response(200, json={"data": []})
                )
                # LXC works for chat completion
                respx.post("http://localhost:9999/v1/chat/completions").mock(
                    return_value=Response(200, json={"choices": [{"message": {"content": "Hello from LXC"}}]})
                )
                transport = ASGITransport(app=main.app)
                async with AsyncClient(transport=transport, base_url="http://test") as ac:
                    resp = await ac.post(
                        "/v1/chat/completions",
                        json={"model": "qwen-3-8b", "messages": [{"role": "user", "content": "hi"}]},
                    )
                assert resp.status_code == 200
                assert resp.json()["choices"][0]["message"]["content"] == "Hello from LXC"

        asyncio.run(run_test())

    def test_all_backends_down_returns_503(self):
        """When all backends are down, router returns 503."""
        async def run_test():
            with respx.mock:
                # Sidecar down
                respx.get("http://localhost:8080/models/status").mock(
                    side_effect=Exception("connection refused")
                )
                # OpenRouter down
                respx.post("https://openrouter.ai/v1/chat/completions").mock(
                    side_effect=Exception("timeout")
                )
                # LXC down
                respx.get("http://localhost:9999/v1/models").mock(
                    side_effect=Exception("connection refused")
                )
                transport = ASGITransport(app=main.app)
                async with AsyncClient(transport=transport, base_url="http://test") as ac:
                    resp = await ac.post(
                        "/v1/chat/completions",
                        json={"model": "qwen-3-8b", "messages": [{"role": "user", "content": "hi"}]},
                    )
                assert resp.status_code == 503

        asyncio.run(run_test())

    def test_lxc_health_check_before_routing(self):
        """Router checks LXC health before routing to it."""
        async def run_test():
            with respx.mock:
                # Sidecar down, OpenRouter down
                respx.get("http://localhost:8080/models/status").mock(
                    side_effect=Exception("connection refused")
                )
                respx.post("https://openrouter.ai/v1/chat/completions").mock(
                    side_effect=Exception("timeout")
                )
                # LXC health check passes
                respx.get("http://localhost:9999/v1/models").mock(
                    return_value=Response(200, json={"data": []})
                )
                # Then the actual chat completion
                respx.post("http://localhost:9999/v1/chat/completions").mock(
                    return_value=Response(200, json={"choices": [{"message": {"content": "LXC"}}]})
                )
                transport = ASGITransport(app=main.app)
                async with AsyncClient(transport=transport, base_url="http://test") as ac:
                    resp = await ac.post(
                        "/v1/chat/completions",
                        json={"model": "qwen-3-8b", "messages": [{"role": "user", "content": "hi"}]},
                    )
                assert resp.status_code == 200

        asyncio.run(run_test())