test: 添加 health.py psycopg3 连接检查单元测试

覆盖 _check_database() 和 _check_migrations() 中的 psycopg.connect 调用：
- 成功连接路径（覆盖 lines 52, 127）
- 连接失败路径
- 内存数据库跳过路径
- startup_check 端点综合测试
预期增量覆盖率从 33% 提升至 100%

tests/unit/test_health_routes.py

@@ -0,0 +1,184 @@
+"""Unit tests for apps/api/app/api/routes/health.py
+
+覆盖 _check_database() 和 _check_migrations() 中 psycopg3 连接逻辑。
+确保增量覆盖率 ≥ 60%（目标覆盖 lines 52, 127）。
+"""
+
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+
+
+@pytest.mark.asyncio
+class TestCheckDatabase:
+    """Tests for _check_database() health check function."""
+
+    @patch("apps.api.app.api.routes.health.settings")
+    @patch("apps.api.app.api.routes.health.psycopg.connect")
+    async def test_check_database_success(self, mock_connect, mock_settings):
+        """PostgreSQL 连接成功时返回 healthy。"""
+        mock_settings.USE_IN_MEMORY_DB = False
+        mock_settings.DATABASE_URL = "postgresql+psycopg://test:test@localhost/test"
+
+        # Mock connection and cursor
+        mock_conn = MagicMock()
+        mock_cursor = MagicMock()
+        mock_cursor.__enter__ = MagicMock(return_value=mock_cursor)
+        mock_cursor.__exit__ = MagicMock(return_value=False)
+        mock_cursor.fetchone.return_value = (1,)
+        mock_conn.cursor.return_value = mock_cursor
+        mock_connect.return_value = mock_conn
+
+        from apps.api.app.api.routes.health import _check_database
+
+        result = await _check_database()
+
+        assert result["status"] == "healthy"
+        assert result["type"] == "postgresql"
+        assert result["message"] == "Database connection successful"
+        mock_connect.assert_called_once_with(
+            "postgresql+psycopg://test:test@localhost/test", connect_timeout=3
+        )
+        mock_cursor.execute.assert_called_once_with("SELECT 1")
+        mock_conn.close.assert_called_once()
+
+    @patch("apps.api.app.api.routes.health.settings")
+    @patch("apps.api.app.api.routes.health.psycopg.connect")
+    async def test_check_database_connection_failure(self, mock_connect, mock_settings):
+        """PostgreSQL 连接失败时返回 unhealthy。"""
+        mock_settings.USE_IN_MEMORY_DB = False
+        mock_settings.DATABASE_URL = "postgresql+psycopg://test:test@localhost/test"
+        mock_connect.side_effect = Exception("connection refused")
+
+        from apps.api.app.api.routes.health import _check_database
+
+        result = await _check_database()
+
+        assert result["status"] == "unhealthy"
+        assert result["type"] == "postgresql"
+        assert "connection refused" in result["message"]
+
+    @patch("apps.api.app.api.routes.health.settings")
+    async def test_check_database_in_memory(self, mock_settings):
+        """使用内存数据库时跳过 PostgreSQL 检查。"""
+        mock_settings.USE_IN_MEMORY_DB = True
+
+        from apps.api.app.api.routes.health import _check_database
+
+        result = await _check_database()
+
+        assert result["status"] == "healthy"
+        assert result["type"] == "in_memory"
+
+
+@pytest.mark.asyncio
+class TestCheckMigrations:
+    """Tests for _check_migrations() health check function."""
+
+    @patch("apps.api.app.api.routes.health.settings")
+    @patch("apps.api.app.api.routes.health.psycopg.connect")
+    async def test_check_migrations_success(self, mock_connect, mock_settings):
+        """所有迁移表存在时返回 healthy。"""
+        mock_settings.USE_IN_MEMORY_DB = False
+        mock_settings.DATABASE_URL = "postgresql+psycopg://test:test@localhost/test"
+
+        mock_conn = MagicMock()
+        mock_cursor = MagicMock()
+        mock_cursor.__enter__ = MagicMock(return_value=mock_cursor)
+        mock_cursor.__exit__ = MagicMock(return_value=False)
+        mock_cursor.fetchone.return_value = (5,)  # 5 tables found
+        mock_conn.cursor.return_value = mock_cursor
+        mock_connect.return_value = mock_conn
+
+        from apps.api.app.api.routes.health import _check_migrations
+
+        result = await _check_migrations()
+
+        assert result["status"] == "healthy"
+        assert result["message"] == "Database migrations applied"
+        mock_connect.assert_called_once_with(
+            "postgresql+psycopg://test:test@localhost/test", connect_timeout=3
+        )
+        mock_conn.close.assert_called_once()
+
+    @patch("apps.api.app.api.routes.health.settings")
+    @patch("apps.api.app.api.routes.health.psycopg.connect")
+    async def test_check_migrations_missing_tables(self, mock_connect, mock_settings):
+        """迁移表不完整时返回 unhealthy。"""
+        mock_settings.USE_IN_MEMORY_DB = False
+        mock_settings.DATABASE_URL = "postgresql+psycopg://test:test@localhost/test"
+
+        mock_conn = MagicMock()
+        mock_cursor = MagicMock()
+        mock_cursor.__enter__ = MagicMock(return_value=mock_cursor)
+        mock_cursor.__exit__ = MagicMock(return_value=False)
+        mock_cursor.fetchone.return_value = (2,)  # Only 2 of 5 tables
+        mock_conn.cursor.return_value = mock_cursor
+        mock_connect.return_value = mock_conn
+
+        from apps.api.app.api.routes.health import _check_migrations
+
+        result = await _check_migrations()
+
+        assert result["status"] == "unhealthy"
+        assert "Missing tables" in result["message"]
+        assert "2/5" in result["message"]
+
+    @patch("apps.api.app.api.routes.health.settings")
+    @patch("apps.api.app.api.routes.health.psycopg.connect")
+    async def test_check_migrations_connection_failure(self, mock_connect, mock_settings):
+        """数据库连接失败时返回 unhealthy。"""
+        mock_settings.USE_IN_MEMORY_DB = False
+        mock_settings.DATABASE_URL = "postgresql+psycopg://test:test@localhost/test"
+        mock_connect.side_effect = Exception("connection refused")
+
+        from apps.api.app.api.routes.health import _check_migrations
+
+        result = await _check_migrations()
+
+        assert result["status"] == "unhealthy"
+        assert "Migration check failed" in result["message"]
+
+    @patch("apps.api.app.api.routes.health.settings")
+    async def test_check_migrations_in_memory(self, mock_settings):
+        """使用内存数据库时跳过迁移检查。"""
+        mock_settings.USE_IN_MEMORY_DB = True
+
+        from apps.api.app.api.routes.health import _check_migrations
+
+        result = await _check_migrations()
+
+        assert result["status"] == "healthy"
+        assert "no migrations needed" in result["message"]
+
+
+@pytest.mark.asyncio
+class TestStartupCheck:
+    """Tests for startup_check() endpoint."""
+
+    @patch("apps.api.app.api.routes.health._check_migrations")
+    @patch("apps.api.app.api.routes.health._check_database")
+    async def test_startup_all_healthy(self, mock_db, mock_mig):
+        """所有检查通过时返回 started。"""
+        mock_db.return_value = {"status": "healthy"}
+        mock_mig.return_value = {"status": "healthy"}
+
+        from apps.api.app.api.routes.health import startup_check
+
+        result = await startup_check()
+
+        assert result["status"] == "started"
+
+    @patch("apps.api.app.api.routes.health._check_migrations")
+    @patch("apps.api.app.api.routes.health._check_database")
+    async def test_startup_db_unhealthy(self, mock_db, mock_mig):
+        """数据库不健康时返回 starting + 503。"""
+        mock_db.return_value = {"status": "unhealthy", "message": "fail"}
+        mock_mig.return_value = {"status": "healthy"}
+
+        from apps.api.app.api.routes.health import startup_check
+
+        result = await startup_check()
+
+        assert result["status"] == "starting"
+        assert result.status_code == 503