nanobot/tests/agent/test_runner_fallback.py
Xubin Ren 43db848db0 Revert "feat(runner): support structured fallback models"
This reverts commit 02b059a616dc6dc82ad15282102c7b27a5a34e40.
2026-05-13 14:11:08 +00:00

365 lines
12 KiB
Python

"""Tests for FallbackProvider model failover."""
from __future__ import annotations
from typing import Any
from unittest.mock import MagicMock
import pytest
from nanobot.providers.base import LLMProvider, LLMResponse
from nanobot.providers.fallback_provider import FallbackProvider
def _make_response(
content: str = "ok",
finish_reason: str = "stop",
*,
error_kind: str | None = None,
) -> LLMResponse:
return LLMResponse(content=content, finish_reason=finish_reason, error_kind=error_kind)
def _error_response(content: str = "api error") -> LLMResponse:
return _make_response(content, finish_reason="error", error_kind="server_error")
class _FakeProvider(LLMProvider):
"""Fake provider for testing."""
def __init__(self, name: str = "fake", response: LLMResponse | None = None):
super().__init__()
self.name = name
self._response = response or _make_response()
self.chat_calls: list[dict[str, Any]] = []
self.chat_stream_calls: list[dict[str, Any]] = []
def get_default_model(self) -> str:
return f"{self.name}/model"
async def chat(self, **kwargs: Any) -> LLMResponse:
self.chat_calls.append(dict(kwargs))
return self._response
async def chat_stream(self, **kwargs: Any) -> LLMResponse:
self.chat_stream_calls.append(dict(kwargs))
on_delta = kwargs.get("on_content_delta")
if on_delta and self._response.content:
await on_delta(self._response.content)
return self._response
# -- config-level tests --
def test_fallback_models_default_empty() -> None:
from nanobot.config.schema import ModelPresetConfig
p = ModelPresetConfig(model="test/model")
assert p.fallback_models == []
def test_fallback_models_accepts_list() -> None:
from nanobot.config.schema import ModelPresetConfig
p = ModelPresetConfig(model="test/primary", fallback_models=["test/a", "test/b"])
assert p.fallback_models == ["test/a", "test/b"]
def test_fallback_models_from_camel_case() -> None:
from nanobot.config.schema import ModelPresetConfig
p = ModelPresetConfig.model_validate({
"model": "test/primary",
"fallbackModels": ["test/a"],
})
assert p.fallback_models == ["test/a"]
# -- FallbackProvider tests --
class TestNoFallbackWhenPrimarySucceeds:
@pytest.mark.asyncio
async def test(self) -> None:
primary = _FakeProvider("primary", _make_response("primary ok"))
factory = MagicMock()
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-a"],
provider_factory=factory,
)
result = await fb.chat(messages=[{"role": "user", "content": "hi"}])
assert result.content == "primary ok"
assert result.finish_reason == "stop"
factory.assert_not_called()
class TestFallbackOnPrimaryError:
@pytest.mark.asyncio
async def test_first_fallback_succeeds(self) -> None:
primary = _FakeProvider("primary", _error_response())
fallback = _FakeProvider("fallback", _make_response("fallback ok"))
factory = MagicMock(return_value=fallback)
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-a"],
provider_factory=factory,
)
result = await fb.chat(messages=[{"role": "user", "content": "hi"}], model="primary-model")
assert result.content == "fallback ok"
assert result.finish_reason == "stop"
factory.assert_called_once_with("fallback-a")
assert primary.chat_calls[0]["model"] == "primary-model"
assert fallback.chat_calls[0]["model"] == "fallback-a"
class TestNoFallbackWhenContentStreamed:
@pytest.mark.asyncio
async def test(self) -> None:
primary = _FakeProvider("primary", _error_response())
factory = MagicMock()
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-a"],
provider_factory=factory,
)
async def _delta(text: str) -> None:
pass
result = await fb.chat_stream(
messages=[{"role": "user", "content": "hi"}],
on_content_delta=_delta,
)
# Primary returns error but content was "streamed" (FakeProvider calls delta)
# so failover should be skipped
assert result.finish_reason == "error"
factory.assert_not_called()
class TestFailoverOnTransientError:
@pytest.mark.asyncio
async def test_rate_limit(self) -> None:
primary = _FakeProvider("primary", _error_response("rate limit exceeded"))
fallback = _FakeProvider("fallback", _make_response("fallback ok"))
factory = MagicMock(return_value=fallback)
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-a"],
provider_factory=factory,
)
result = await fb.chat(messages=[{"role": "user", "content": "hi"}])
assert result.content == "fallback ok"
assert result.finish_reason == "stop"
factory.assert_called_once_with("fallback-a")
@pytest.mark.asyncio
async def test_timeout(self) -> None:
primary = _FakeProvider(
"primary",
_make_response("timed out", finish_reason="error", error_kind="timeout"),
)
fallback = _FakeProvider("fallback", _make_response("fallback ok"))
factory = MagicMock(return_value=fallback)
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-a"],
provider_factory=factory,
)
result = await fb.chat(messages=[{"role": "user", "content": "hi"}])
assert result.content == "fallback ok"
assert result.finish_reason == "stop"
factory.assert_called_once_with("fallback-a")
class TestFallbackTriesModelsInOrder:
@pytest.mark.asyncio
async def test(self) -> None:
primary = _FakeProvider("primary", _error_response("primary fail"))
fallback_a = _FakeProvider("a", _error_response("a fail"))
fallback_b = _FakeProvider("b", _make_response("b ok"))
factory = MagicMock(side_effect=[fallback_a, fallback_b])
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-a", "fallback-b"],
provider_factory=factory,
)
result = await fb.chat(messages=[{"role": "user", "content": "hi"}])
assert result.content == "b ok"
assert factory.call_count == 2
factory.assert_any_call("fallback-a")
factory.assert_any_call("fallback-b")
class TestAllFallbacksFail:
@pytest.mark.asyncio
async def test(self) -> None:
primary = _FakeProvider("primary", _error_response("primary fail"))
fallback = _FakeProvider("fallback", _error_response("all fail"))
factory = MagicMock(return_value=fallback)
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-a"],
provider_factory=factory,
)
result = await fb.chat(messages=[{"role": "user", "content": "hi"}])
assert result.finish_reason == "error"
assert "all fail" in result.content
class TestFactoryExceptionSkipsModel:
@pytest.mark.asyncio
async def test(self) -> None:
primary = _FakeProvider("primary", _error_response())
fallback_b = _FakeProvider("b", _make_response("b ok"))
factory = MagicMock(side_effect=[ValueError("no key"), fallback_b])
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-a", "fallback-b"],
provider_factory=factory,
)
result = await fb.chat(messages=[{"role": "user", "content": "hi"}])
assert result.content == "b ok"
assert factory.call_count == 2
class TestFallbackModelParameter:
@pytest.mark.asyncio
async def test(self) -> None:
"""Fallback calls should use the fallback model name."""
primary = _FakeProvider("primary", _error_response())
fallback = _FakeProvider("fallback", _make_response("ok"))
factory = MagicMock(return_value=fallback)
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-model"],
provider_factory=factory,
)
await fb.chat(messages=[{"role": "user", "content": "hi"}], model="primary-model")
assert fallback.chat_calls[0]["model"] == "fallback-model"
class TestNoFallbackWhenEmptyList:
@pytest.mark.asyncio
async def test(self) -> None:
primary = _FakeProvider("primary", _error_response())
factory = MagicMock()
fb = FallbackProvider(
primary=primary,
fallback_models=[],
provider_factory=factory,
)
result = await fb.chat(messages=[{"role": "user", "content": "hi"}])
assert result.finish_reason == "error"
factory.assert_not_called()
class TestChatStreamFailover:
@pytest.mark.asyncio
async def test_fallback_succeeds(self) -> None:
# Use empty content so on_content_delta is not triggered on the error
primary = _FakeProvider("primary", _error_response(""))
fallback = _FakeProvider("fallback", _make_response("stream ok"))
factory = MagicMock(return_value=fallback)
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-a"],
provider_factory=factory,
)
result = await fb.chat_stream(messages=[{"role": "user", "content": "hi"}])
assert result.content == "stream ok"
assert result.finish_reason == "stop"
class TestGetDefaultModel:
def test(self) -> None:
primary = _FakeProvider("primary")
fb = FallbackProvider(
primary=primary,
fallback_models=["a"],
provider_factory=MagicMock(),
)
assert fb.get_default_model() == "primary/model"
class TestCircuitBreaker:
@pytest.mark.asyncio
async def test_skips_primary_after_three_failures(self) -> None:
primary = _FakeProvider("primary", _error_response())
fallback = _FakeProvider("fallback", _make_response("fallback ok"))
factory = MagicMock(return_value=fallback)
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-a"],
provider_factory=factory,
)
# 3 failures — primary should still be called each time
for _ in range(3):
result = await fb.chat(messages=[{"role": "user", "content": "hi"}])
assert result.content == "fallback ok"
assert len(primary.chat_calls) == 3
# 4th call — primary circuit is open, should be skipped
primary.chat_calls.clear()
result = await fb.chat(messages=[{"role": "user", "content": "hi"}])
assert result.content == "fallback ok"
assert len(primary.chat_calls) == 0
@pytest.mark.asyncio
async def test_resets_on_success(self) -> None:
primary = _FakeProvider("primary", _error_response())
fallback = _FakeProvider("fallback", _make_response("fallback ok"))
factory = MagicMock(return_value=fallback)
fb = FallbackProvider(
primary=primary,
fallback_models=["fallback-a"],
provider_factory=factory,
)
# 2 failures
for _ in range(2):
await fb.chat(messages=[{"role": "user", "content": "hi"}])
# 3rd call: primary succeeds — circuit resets
primary._response = _make_response("primary ok")
result = await fb.chat(messages=[{"role": "user", "content": "hi"}])
assert result.content == "primary ok"
# 4th call: primary fails again — should still be called (counter reset)
primary._response = _error_response()
primary.chat_calls.clear()
result = await fb.chat(messages=[{"role": "user", "content": "hi"}])
assert result.content == "fallback ok"
assert len(primary.chat_calls) == 1
class TestGenerationForwarded:
def test(self) -> None:
from nanobot.providers.base import GenerationSettings
primary = _FakeProvider("primary")
primary.generation = GenerationSettings(temperature=0.5, max_tokens=1024)
fb = FallbackProvider(
primary=primary,
fallback_models=["a"],
provider_factory=MagicMock(),
)
assert fb.generation.temperature == 0.5
assert fb.generation.max_tokens == 1024