为mysql数据库调用创建jest测试文件

npm install --save-dev jest

yarn add --dev jest

const mysql = require('mysql');

// 测试连接数据库
test('测试连接数据库', () => {
  const connection = mysql.createConnection({
    host: 'localhost',
    user: 'root',
    password: 'password',
    database: 'mydatabase',
  });

  connection.connect((err) => {
    expect(err).toBeNull();
    connection.end();
  });
});

// 测试查询数据
test('测试查询数据', () => {
  const connection = mysql.createConnection({
    host: 'localhost',
    user: 'root',
    password: 'password',
    database: 'mydatabase',
  });

  connection.query('SELECT * FROM users', (err, results) => {
    expect(err).toBeNull();
    expect(results.length).toBeGreaterThan(0);
    connection.end();
  });
});