feat: 添加模型上下文管理并统一主题组件与用量交互

backend/tests/test_context_budget.py

@@ -0,0 +1,144 @@
+import asyncio
+from functools import wraps
+from unittest.mock import AsyncMock
+
+import pytest
+from pydantic import ValidationError
+
+from app.contracts import Message, ModelContextPolicy, ModelRequest, ProviderConfig
+from app.providers.base import ProviderError, ProviderTurn
+from app.providers.context_budget import prepare_context
+from app.providers.factory import ProviderFactory
+
+
+def async_test(fn):
+    @wraps(fn)
+    def run(*args, **kwargs):
+        return asyncio.run(fn(*args, **kwargs))
+    return run
+
+
+def config(mode="detect", **kwargs):
+    return ProviderConfig(provider_id="p", provider_type="openai_compatible", name="test",
+        context_policies=[ModelContextPolicy(model="test", context_window=8192, output_reserve=512,
+                                            threshold=0.1, mode=mode, **kwargs)])
+
+
+def request():
+    return ModelRequest(provider_id="p", model="test", system="Keep this system instruction",
+        messages=[Message(role="user", content="旧文本" * 500), Message(role="assistant", content="历史答复"),
+                  Message(role="user", content="继续"), Message(role="assistant", content="近期答复"),
+                  Message(role="user", content="最新问题")])
+
+
+@async_test
+async def test_threshold_detect_blocks_before_network():
+    complete = AsyncMock()
+    with pytest.raises(ProviderError, match="已达到") as error:
+        await prepare_context(request(), config(), complete)
+    assert error.value.code == "CONTEXT_COMPRESSION_REQUIRED"
+    complete.assert_not_called()
+
+
+@async_test
+async def test_compress_preserves_archive_system_and_recent_turns():
+    original = request()
+    copy = original.model_dump()
+    complete = AsyncMock(return_value=ProviderTurn(text="已讨论旧文本。"))
+    prepared = await prepare_context(original, config("compress", prompt="自定义摘要指令"), complete)
+    assert original.model_dump() == copy
+    assert prepared.system == original.system
+    assert prepared.messages[-3:] == original.messages[-3:]
+    assert prepared.max_tokens == 512
+    assert complete.call_args.args[0].system == "自定义摘要指令"
+    assert not complete.call_args.args[0].tools
+
+
+@async_test
+async def test_unknown_model_unmodified():
+    original = request().model_copy(update={"model": "other"})
+    complete = AsyncMock()
+    assert await prepare_context(original, config(), complete) is original
+    complete.assert_not_called()
+
+
+@async_test
+async def test_single_oversize_turn_is_not_discarded():
+    original = request().model_copy(update={"messages": request().messages[:1]})
+    complete = AsyncMock()
+    with pytest.raises(ProviderError, match="没有可压缩"):
+        await prepare_context(original, config("compress"), complete)
+    complete.assert_not_called()
+
+
+@async_test
+async def test_tool_history_is_not_split():
+    original = request()
+    original.messages.insert(2, Message(role="tool", content="result", tool_call_id="call"))
+    complete = AsyncMock()
+    with pytest.raises(ProviderError, match="工具调用历史"):
+        await prepare_context(original, config("compress"), complete)
+    complete.assert_not_called()
+
+
+@async_test
+async def test_ineffective_summary_fails_without_mutation():
+    original = request()
+    copy = original.model_dump()
+    with pytest.raises(ProviderError, match="未缩短"):
+        await prepare_context(original, config("compress"), AsyncMock(return_value=ProviderTurn(text="长" * 6000)))
+    assert original.model_dump() == copy
+
+
+@async_test
+async def test_override_output_budget_is_counted():
+    settings = config()
+    from app.request_overrides import RequestOverride
+    settings.request_overrides = [RequestOverride(body={"max_completion_tokens": 9000})]
+    with pytest.raises(ProviderError, match="占满"):
+        await prepare_context(request(), settings, AsyncMock())
+
+
+@async_test
+async def test_factory_stream_exposes_actionable_error_without_network():
+    adapter = ProviderFactory(None).build(config())
+    events = [event async for event in adapter.stream(request())]
+    assert [e.event.value for e in events] == ["Error", "Done"]
+    assert events[0].data["code"] == "CONTEXT_COMPRESSION_REQUIRED"
+
+
+def test_invalid_and_duplicate_config_rejected():
+    with pytest.raises(ValidationError):
+        ModelContextPolicy(model="test", context_window=1024, output_reserve=1024)
+    settings = config().model_dump()
+    settings["context_policies"] *= 2
+    with pytest.raises(ValidationError, match="同一模型"):
+        ProviderConfig.model_validate(settings)
+
+
+@async_test
+async def test_factory_compression_status_and_usage_request_are_separate(monkeypatch):
+    from datetime import datetime, timezone
+    from app.contracts import ModelEvent, ModelEventType
+    from app.services.usage_service import usage_context
+    seen = []
+
+    class Adapter:
+        async def complete(self, req):
+            seen.append((req, usage_context.get()))
+            return ProviderTurn(text="历史摘要。")
+
+        async def stream(self, req):
+            seen.append((req, usage_context.get()))
+            yield ModelEvent(event=ModelEventType.text_delta, timestamp=datetime.now(timezone.utc), data={"text": "回答"})
+            yield ModelEvent(event=ModelEventType.done, timestamp=datetime.now(timezone.utc), data={"status": "completed"})
+
+    factory = ProviderFactory(None)
+    monkeypatch.setattr(factory, "_build", lambda _: Adapter())
+    adapter = factory.build(config("compress"))
+    original = request()
+    events = [event async for event in adapter.stream(original)]
+    assert [e.event.value for e in events] == ["ContextStatus", "TextDelta", "Done"]
+    assert [e.sequence for e in events] == [0, 1, 2]
+    assert seen[0][1]["request_id"] != seen[1][1]["request_id"]
+    assert seen[1][0].messages[-3:] == original.messages[-3:]

backend/tests/test_usage_overrides.py

@@ -114,3 +114,19 @@ def test_usage_calendar_series_splits_sources_and_preserves_missing_counters():
     filtered = aggregate(start, start + timedelta(days=2), source='local', timezone_offset=480)
     assert all(b['api']['requests'] == 0 for b in filtered['series'])
     assert len(aggregate(start, start + timedelta(days=3660))['series']) <= 90
+
+
+def test_model_series_partitions_match_source_totals_and_cache_rate():
+    start = datetime(2026, 9, 1, tzinfo=timezone.utc)
+    for model, count in [('model-a', 100), ('model-b', 200)]:
+        attempt = UsageAttempt('p', model, 'openai_compatible')
+        attempt.started_at = start.isoformat()
+        attempt.observe({'usage': {'prompt_tokens': count, 'completion_tokens': 0, 'prompt_cache_hit_tokens': 20, 'prompt_cache_miss_tokens': count - 20}})
+        attempt.persist()
+    result = aggregate(start, start + timedelta(days=1))
+    api = result['series'][0]['api']
+    assert [part['model'] for part in api['models']] == ['model-a', 'model-b']
+    assert sum(part['totals']['input_tokens'] for part in api['models']) == api['totals']['input_tokens'] == 300
+    assert result['totals']['cache_hit_tokens'] == 40
+    assert result['totals']['cache_miss_tokens'] == 260
+    assert result['cache_hit_rate'] == pytest.approx(40/300)