如何在单元测试时异步地从db中获取记录？

npm install mysql2/promise

const mysql = require('mysql2/promise');

// 模拟数据库配置
const dbConfig = {
  host: 'localhost',
  user: 'testuser',
  password: 'testpass',
  database: 'testdb'
};

// 异步函数，用于从数据库获取记录
async function fetchRecord(id) {
  const connection = await mysql.createConnection(dbConfig);
  try {
    const [rows] = await connection.execute('SELECT * FROM users WHERE id = ?', [id]);
    return rows[0];
  } finally {
    connection.end();
  }
}

// 单元测试
describe('fetchRecord', () => {
  it('should fetch a record by id', async () => {
    const record = await fetchRecord(1);
    expect(record).toEqual({ id: 1, name: 'Test User' });
  });

  it('should return null for non-existent id', async () => {
    const record = await fetchRecord(999);
    expect(record).toBeNull();
  });
});