main:新增中间件测试用例

变更内容：
- 为路径规范化函数添加单元测试，验证 /jobs 等路径的行为。
- 为指标中间件编写测试，包括健康检查端点跳过和普通端点的指标记录。
- 检查任务路径规范化逻辑并验证规范化后的路径是否正确。

tests/test_middleware.py

@@ -0,0 +1,97 @@
+"""中间件测试"""
+
+import pytest
+from unittest.mock import patch, MagicMock
+from fastapi.testclient import TestClient
+
+from src.functional_scaffold.main import app, normalize_path
+
+
+class TestNormalizePath:
+    """测试路径规范化函数"""
+
+    def test_normalize_jobs_path(self):
+        """测试 /jobs/{job_id} 路径规范化"""
+        assert normalize_path("/jobs/a1b2c3d4e5f6") == "/jobs/{job_id}"
+        assert normalize_path("/jobs/123456789012") == "/jobs/{job_id}"
+        assert normalize_path("/jobs/xyz") == "/jobs/{job_id}"
+
+    def test_normalize_other_paths(self):
+        """测试其他路径保持不变"""
+        assert normalize_path("/invoke") == "/invoke"
+        assert normalize_path("/healthz") == "/healthz"
+        assert normalize_path("/readyz") == "/readyz"
+        assert normalize_path("/metrics") == "/metrics"
+        assert normalize_path("/docs") == "/docs"
+
+    def test_normalize_jobs_root(self):
+        """测试 /jobs 根路径"""
+        assert normalize_path("/jobs") == "/jobs"
+
+
+class TestMetricsMiddleware:
+    """测试指标中间件"""
+
+    @patch("src.functional_scaffold.main.incr")
+    @patch("src.functional_scaffold.main.observe")
+    @patch("src.functional_scaffold.main.gauge_incr")
+    @patch("src.functional_scaffold.main.gauge_decr")
+    def test_skip_health_endpoints(self, mock_gauge_decr, mock_gauge_incr, mock_observe, mock_incr):
+        """测试跳过健康检查端点"""
+        client = TestClient(app)
+
+        # 访问健康检查端点
+        client.get("/healthz")
+        client.get("/readyz")
+        client.get("/metrics")
+
+        # 验证没有记录指标
+        mock_incr.assert_not_called()
+        mock_observe.assert_not_called()
+        mock_gauge_incr.assert_not_called()
+        mock_gauge_decr.assert_not_called()
+
+    @patch("src.functional_scaffold.main.incr")
+    @patch("src.functional_scaffold.main.observe")
+    @patch("src.functional_scaffold.main.gauge_incr")
+    @patch("src.functional_scaffold.main.gauge_decr")
+    def test_record_normal_endpoints(self, mock_gauge_decr, mock_gauge_incr, mock_observe, mock_incr):
+        """测试记录普通端点"""
+        client = TestClient(app)
+
+        # 访问普通端点
+        client.post("/invoke", json={"number": 17})
+
+        # 验证记录了指标
+        mock_gauge_incr.assert_called_once()
+        mock_gauge_decr.assert_called_once()
+        mock_incr.assert_called_once()
+        mock_observe.assert_called_once()
+
+        # 验证使用了正确的端点路径
+        incr_call_args = mock_incr.call_args
+        assert incr_call_args[0][1]["endpoint"] == "/invoke"
+
+    @patch("src.functional_scaffold.main.incr")
+    @patch("src.functional_scaffold.main.observe")
+    @patch("src.functional_scaffold.main.gauge_incr")
+    @patch("src.functional_scaffold.main.gauge_decr")
+    @patch("src.functional_scaffold.core.job_manager.get_job_manager")
+    def test_normalize_job_path(self, mock_get_manager, mock_gauge_decr, mock_gauge_incr, mock_observe, mock_incr):
+        """测试规范化任务路径"""
+        # Mock job manager
+        mock_manager = MagicMock()
+        mock_manager.get_job.return_value = None
+        mock_get_manager.return_value = mock_manager
+
+        client = TestClient(app)
+
+        # 访问任务端点（会返回 404，但中间件应该记录指标）
+        client.get("/jobs/a1b2c3d4e5f6")
+
+        # 验证记录了指标
+        mock_incr.assert_called_once()
+
+        # 验证使用了规范化后的路径
+        incr_call_args = mock_incr.call_args
+        assert incr_call_args[0][1]["endpoint"] == "/jobs/{job_id}"