P1-1 后端核心模块单测 (20260810-154318)

新增 test_capability_discovery.py (30) + test_llm_router.py (21) 共 51 个哨兵单测,覆盖 #874 双 Claw 能力发现 / #875 LLM 路由熔断 / #876 OTel 桥接关键路径. 套件: 116 -> 165 passed.

tests/test_llm_router.py

@@ -0,0 +1,267 @@
+"""P1-1: 单测 — llm_router 路由/熔断/上下文(双 Claw 共享 #875)。
+
+为什么这个文件存在:
+    LLM Router 是 #875 加速带的关键能力,但 #937 副密钥 failover 设计依托
+    同一熔断 / 决策路径。锁死关键纯函数 + mock 路径,防止回归。
+
+验证范围:
+    1. 上下文注入: set_route_ctx → get_route_ctx 含 tenant/claw/trace
+    2. OTel 桥接: set_route_ctx 同步注入 OTel 双 Claw 标签
+    3. _is_text_only: 排除 media-only 模型(关键坑:failover 误用图像模型给文本)
+    4. _tenant_authorized: 全局 / 私有模型归属校验
+    5. _fallbacks: 排除 exclude_ids + 仅纯文本 + is_default desc
+    6. 熔断: report_failure ×3 → _fail_count = 3(内存降级)
+    7. 熔断: report_success 清零
+    8. 熔断: TTL 过期自动清零
+    9. RouteDecision 数据类可序列化 / 字段完整
+"""
+from __future__ import annotations
+
+import os
+import sys
+import time
+
+import pytest
+
+_HERE = os.path.dirname(os.path.abspath(__file__))
+sys.path.insert(0, os.path.join(_HERE, ".."))
+
+from app.core import llm_router as lr  # noqa: E402
+from app.core.llm_router import (  # noqa: E402
+    SHADOW,
+    _is_text_only,
+    _tenant_authorized,
+    _fallbacks,
+    _fail_count,
+    _BREAKER_LOCAL,
+    report_failure,
+    report_success,
+    set_route_ctx,
+    get_route_ctx,
+    RouteDecision,
+)
+
+
+# =====================================================================
+# 1. 上下文注入
+# =====================================================================
+
+def test_set_route_ctx_default():
+    set_route_ctx()
+    ctx = get_route_ctx()
+    assert ctx["claw_type"] == "web"
+    assert ctx["tenant_id"] == ""
+    assert "trace_id" in ctx
+
+
+def test_set_route_ctx_im():
+    set_route_ctx(tenant_id="t-1", claw_type="im")
+    ctx = get_route_ctx()
+    assert ctx["tenant_id"] == "t-1"
+    assert ctx["claw_type"] == "im"
+
+
+def test_set_route_ctx_otel_bridge(monkeypatch):
+    """set_route_ctx 应同步注入 OTel 双 Claw 标签"""
+    captured = {}
+
+    def fake_set_otel_ctx(*, tenant_id, claw_type):
+        captured["tenant_id"] = tenant_id
+        captured["claw_type"] = claw_type
+
+    # patch the lazy import target
+    import app.core.otel as otel_mod
+    monkeypatch.setattr(otel_mod, "set_otel_ctx", fake_set_otel_ctx)
+    set_route_ctx(tenant_id="t-9", claw_type="im")
+    assert captured == {"tenant_id": "t-9", "claw_type": "im"}
+
+
+def test_set_route_ctx_otel_silently_swallows_failure(monkeypatch):
+    """otel 不可用时静默跳过,不冒泡"""
+    import app.core.otel as otel_mod
+    def boom(**kw):
+        raise RuntimeError("otel down")
+    monkeypatch.setattr(otel_mod, "set_otel_ctx", boom)
+    # 应不抛
+    set_route_ctx(tenant_id="t-x", claw_type="web")
+
+
+# =====================================================================
+# 2. _is_text_only — failover 备选关键判断
+# =====================================================================
+
+class FakeModel:
+    def __init__(self, capabilities):
+        self.capabilities = capabilities
+
+
+def test_is_text_only_pure_text():
+    assert _is_text_only(FakeModel(["text"])) is True
+
+
+def test_is_text_only_excludes_image():
+    """纯图像模型不是文本 failover 备选"""
+    assert _is_text_only(FakeModel(["image"])) is False
+
+
+def test_is_text_only_excludes_mixed_with_media():
+    """含 text 但同时有 image → 视为媒体"""
+    assert _is_text_only(FakeModel(["text", "image"])) is False
+
+
+def test_is_text_only_handles_empty():
+    assert _is_text_only(FakeModel([])) is False
+    assert _is_text_only(FakeModel(None)) is False
+
+
+# =====================================================================
+# 3. _tenant_authorized
+# =====================================================================
+
+class FakeModelWithTenant:
+    def __init__(self, tenant_id):
+        self.tenant_id = tenant_id
+
+
+def test_tenant_authorized_global_open():
+    """全局模型(无 tenant_id)任何人可用"""
+    m = FakeModelWithTenant(None)
+    assert _tenant_authorized(m, "t-1") is True
+    assert _tenant_authorized(m, "") is True
+
+
+def test_tenant_authorized_private_match():
+    m = FakeModelWithTenant("t-1")
+    assert _tenant_authorized(m, "t-1") is True
+
+
+def test_tenant_authorized_private_mismatch():
+    m = FakeModelWithTenant("t-1")
+    assert _tenant_authorized(m, "t-2") is False
+
+
+def test_tenant_authorized_no_tenant_blocked():
+    """私有模型 + caller 没传 tenant → 拒绝"""
+    m = FakeModelWithTenant("t-1")
+    assert _tenant_authorized(m, "") is False
+
+
+# =====================================================================
+# 4. _fallbacks: 排除 exclude_ids + 纯文本 + is_default desc
+# =====================================================================
+
+class FakeAimModel:
+    def __init__(self, id, capabilities, is_default=False, is_enabled=True):
+        self.id = id
+        self.capabilities = capabilities
+        self.is_default = is_default
+        self.is_enabled = is_enabled
+
+
+class FakeDb:
+    def __init__(self, rows):
+        self._rows = rows
+    def query(self, cls):
+        rows = self._rows
+        class Q:
+            def filter(self_inner, *a, **kw):
+                return self_inner
+            def order_by(self_inner, *a, **kw):
+                return self_inner
+            def all(self_inner):
+                return rows
+        return Q()
+
+
+def test_fallbacks_excludes_exclude_ids():
+    db = FakeDb([
+        FakeAimModel("a", ["text"], is_default=True),
+        FakeAimModel("b", ["text"], is_default=False),
+    ])
+    out = _fallbacks(db, exclude_ids={"a"}, limit=4)
+    assert [m.id for m in out] == ["b"]
+
+
+def test_fallbacks_excludes_media():
+    db = FakeDb([
+        FakeAimModel("a", ["text"], is_default=True),
+        FakeAimModel("b", ["image"], is_default=True),  # 媒体不算
+    ])
+    out = _fallbacks(db, exclude_ids=set(), limit=4)
+    assert [m.id for m in out] == ["a"]
+
+
+def test_fallbacks_limit_caps():
+    db = FakeDb([
+        FakeAimModel(f"m{i}", ["text"], is_default=False) for i in range(10)
+    ])
+    out = _fallbacks(db, exclude_ids=set(), limit=3)
+    assert len(out) == 3
+
+
+# =====================================================================
+# 5. 熔断: 内存降级(无 Redis)
+# =====================================================================
+
+def setup_function(_):
+    """每个测试前清空内存 breaker 状态"""
+    _BREAKER_LOCAL.clear()
+
+
+def test_breaker_increments_and_reads():
+    report_failure("m-1")
+    report_failure("m-1")
+    report_failure("m-1")
+    assert _fail_count("m-1") == 3
+
+
+def test_breaker_success_clears():
+    report_failure("m-2")
+    report_failure("m-2")
+    assert _fail_count("m-2") == 2
+    report_success("m-2")
+    assert _fail_count("m-2") == 0
+
+
+def test_breaker_ttl_expires(monkeypatch):
+    """TTL 过期后 _fail_count 返回 0,本地条目清理"""
+    report_failure("m-3")
+    # 假装时间穿越到未来(after TTL)
+    fake_now = time.time() + 1000
+    monkeypatch.setattr(lr.time, "time", lambda: fake_now)
+    assert _fail_count("m-3") == 0
+    assert "m-3" not in _BREAKER_LOCAL
+
+
+def test_breaker_empty_model_id():
+    report_failure("")
+    assert _fail_count("") == 0
+
+
+# =====================================================================
+# 6. RouteDecision 数据类
+# =====================================================================
+
+def test_route_decision_defaults():
+    rd = RouteDecision(capability="text", claw_type="web", tenant_id="t-1")
+    assert rd.capability == "text"
+    assert rd.claw_type == "web"
+    assert rd.tenant_id == "t-1"
+    assert rd.models == []
+    assert rd.primary is None
+    assert rd.shadow is True
+    assert rd.matched_legacy is None
+    assert rd.reason == ""
+
+
+def test_route_decision_fields_assignable():
+    rd = RouteDecision(capability="text", claw_type="im", tenant_id="t-1")
+    rd.models = ["a", "b"]
+    rd.primary = "a"
+    rd.reason = "explicit"
+    rd.matched_legacy = True
+    assert rd.models == ["a", "b"]
+    assert rd.primary == "a"
+    assert rd.reason == "explicit"
+    assert rd.matched_legacy is True
+