在针对Knex进行单元测试时，如何模拟假数据库?

问题描述

我一直在成功使用 Knex 连接到后端数据库.但是我希望能够对我的代码进行单元测试.有没有办法模拟数据库连接?

I've been using Knex successfully to connect to a backend database. But I want to be able to unit test my code. Is there a way to mock the database connection?

我尝试使用 proxyquire ，但似乎无法正常工作.

I've tried using proxyquire but I can't seem to get it to work.

问题似乎与Knex的初始化方式有关.

The problem seems to be with the way Knex is initialized.

var knex = require('knex')({
  client: 'mysql',
  connection: {}
});

我设置了在我的单元测试中要模拟的knex.

I setup knex to be mocked in my unit test.

myService = proxyquire('../app/myService', {
        'knex': knexProxy
});

我的服务包括knex.

My service includes knex.

var knex = require('knex').knex,

当我的服务运行查询时，它将失败.

When my service runs a query, it fails.

var sql = knex("table_name");
sql.insert(rowToInsert, "auto_increment_id");
sql.then(function (insertId) {
    resolve();
}, function (err) {
    reject(err);
});

由于某种原因，我似乎无法在尝试连接之前捕获该请求.

For some reason I just can't seem to capture the request before it attempts the connection.

我也尝试创建自定义Knex客户端，但这没有用还是.

I've also, tried to create a custom Knex Client, but that hasn't worked yet either.

推荐答案

使用笑话:

在您的应用程序根目录中创建文件/__mocks__/knex.js:

Create the file /__mocks__/knex.js in your app root:

module.exports = () => ({
  select: jest.fn().mockReturnThis(),
  from: jest.fn().mockReturnThis(),
  where: jest.fn().mockReturnThis(),
  first: jest.fn().mockReturnThis(),
  then: jest.fn(function (done) {
    done(null)
  })
})

将所需的返回值传递给done

Pass the desired return value to done

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