如何在节点中模拟 SQL Server 连接池答案

【问题标题】：How to mock SQL Server connection pool in node如何在节点中模拟 SQL Server 连接池
【发布时间】：2021-11-21 01:40:33
【问题描述】：

我正在尝试模拟 SQL Server 连接池，以便测试 DAL 的功能。

我有一个连接池文件

connectionPool.js

const sql = require('mssql');
const log = require('../services/logger');

const config = {
  user: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  server: process.env.SERVER,
  database: process.env.DATABASE
};

const poolPromise = new sql.ConnectionPool(config)
  .connect()
  .then(pool => {
    log.info('Connected to SQL Server');
    return pool;
  })
  .catch(err => {
    log.error(err, 'Database connection failed');
  });

module.exports = poolPromise;

我在 DAL 中使用它。非常精简，但必需品在那里。

const {poolPromise} = require('./connectionPool');

const getData = async () => {
  const pool = await poolPromise;
  const request = pool.request()
  const result = await request('SELECT * FROM table');
}

这样，每个应用程序只创建一次连接池。（见How can I use a single mssql connection pool across several routes in an Express 4 web application?）

我想模拟mssql 模块，以便连接池功能仍然有效。我尝试了多种选择。 How to mock SQL Server connection pool using Jest? 让我很接近，但它并不完全在那里。

__mocks/mssql.js

const mockExecute = jest.fn();
const mockInput = jest.fn(() => ({ execute: mockExecute }));
const mockRequest = jest.fn(() => ({ input: mockInput }));

jest.mock('mssql', () => ({
  ConnectionPool: jest.fn(() => ({request: mockRequest})),
  NVarChar: jest.fn()
}));

const sql = require('mssql');

module.exports = sql;

但是我得到了错误

TypeError: (中间值).connect 不是函数

17 |
18 | const poolPromise = new sql.ConnectionPool(config)
19 | .connect()
| ^
20 | .then(池 => {
21 | log.info('连接到 SQL Server');
22 |返回池；

【问题讨论】：

标签： node.js jestjs node-mssql

【解决方案1】：

这可能是一个解决方案。 connectionPool.js 的一点重构

const sql = require('mssql');
const log = require('../services/logger');

const config = {
  user: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  server: process.env.SERVER,
  database: process.env.DATABASE
};
if (process.env.NODE_ENV === 'development') {
  config.options = {
    encrypt: false,
    trustServerCertificate: true
  };
}

const connectionPool = new sql.ConnectionPool(config);
const poolPromise = connectionPool
  .connect()
  .then(pool => {
    log.info('Connected to MSSQL');
    return pool;
  })
  .catch(err => {
    log.error(err, 'Database connection failed');
  });

module.exports = poolPromise;

然后在/__mocks__/mssql.js

'use strict';

const mockExecute = jest.fn();
const mockInput = jest.fn().mockReturnValue({ execute: mockExecute });
const mockQuery = jest.fn().mockReturnValue({recordset: 'Mock data'});
const mockRequest = jest.fn().mockReturnValue({
  input: mockInput,
  query: mockQuery
});

const mockTransaction = jest.fn().mockImplementation(() => {
  return {
    begin: callback => callback(),
    commit: jest.fn(),
    rollback: jest.fn()
  };
});

const mockConnect = jest.fn().mockImplementation(() => {
  return Promise.resolve({ transaction: mockTransaction });
});

jest.mock('mssql', () => ({
  ConnectionPool: jest.fn().mockReturnValue({
    request: mockRequest,
    connect: mockConnect
  }),
  Request: mockRequest,
  NVarChar: jest.fn()
}));

const mssql = require('mssql');

module.exports = mssql;

它似乎有效，但我不确定它是否正确

【讨论】：