Mocha用Knex测试PostgreSQL给我一个MigrationLocked错误 [英] Mocha testing PostgreSQL with Knex is giving me a MigrationLocked error

问题描述

在某种程度上，我可以使用Node/PostgreSQL/Knex开发本地开发环境，因为我可以使用API​​将其发布到机器上的开发数据库中.我现在正在尝试为此功能创建测试，但出现错误.

I have got a local development environment working for Node/PostgreSQL/Knex in the sense that I can post to a development database on my machine using an API. I am now trying to create tests for this functionality but am getting an error.

这是我的配置:

//knexfile.js
module.exports = {
  development: {
    client: 'pg',
    connection: {
        host: '127.0.0.1',
        user: 'dbUser',
        password: 'dbpword',
        port: 5432,
        database: 'example-name'
    },
    migrations: {
      directory: __dirname + '/db/migrations'
    },
    seeds: {
      directory: __dirname + '/db/seeds/development'
    }
  },
}

//db.js
const config = require('../knexfile.js');
const env = process.env.NODE_ENV || 'development';
const knex = require("knex")(config[env]);

module.exports = knex;

knex.migrate.latest([config]);

然后是我的测试:

import chai from 'chai';
import { expect } from 'chai';
import chaiHttp from 'chai-http';
import knex from '../../db/db';
import app from '../../server';

chai.use(chaiHttp);

describe('Tokens API', () => {

  beforeEach((done) => {
   knex.migrate.rollback()
   .then(() => {
     knex.migrate.latest()
     .then(() => {
       return knex.seed.run()
       .then(() => {
        done();
       });
     });
   });
});

afterEach((done) => {
  knex.migrate.rollback()
  .then(() => {
    done();
  });
});

describe('POST /users', () => {
  it('posts a list of users to the database with all mandatory fields', (done) => {
    chai.request(app)
    .post('/users')
    .send({
        "users": [
              "steve",
              "whoever",
              "matt",
              "another"]})
      .end((err, res) => {
        expect(err).to.be.null;
        expect(res).to.have.status(200);
        expect(res).to.be.json;
        done();
      });
    });
  });
});

运行此命令时，两次出现以下错误-我认为对于beforeEach块中的knex调用:

When I run this I get the following error twice - I think for the knex calls in the beforeEach block:

Knex:warning - Can't take lock to run migrations: Migration table is already locked
Knex:warning - If you are sure migrations are not running you can release the lock manually by deleting all the rows from migrations lock table: knex_migrations_lock
Unhandled rejection MigrationLocked: Migration table is already locked

我尝试了很多事情-包括清除knex_migrations_lock表.我在网上可以找到的唯一支持是此线程，该线程建议使用以下方法清除锁表DELETE FROM Migrations_lock where id <> 0;，但是我的锁表只有一个is_locked列，其值为零.

I have tried numerous things - including clearing out the knex_migrations_lock table. The only support I can find online is this thread, which suggests clearing out the lock table using DELETE FROM Migrations_lock where id <> 0;, however my lock table only has a is_locked column with zero values.

知道发生了什么事吗?

我刚刚意识到，如果您删除所有的knex调用，则测试实际上会通过.可能是因为我实际上两次调用过knex-一次是从db.js调用，一次是间接地通过server.js调用吗?如果是这样，我该如何避免这样做-因为我确实需要调用Node的knex设置才能运行它?

I've just realised if you edit out all the knex calls, the test actually passes. Could this be because I am effectively calling knex twice - once from db.js and once indirectly through server.js? If that's the case, how do I avoid doing this - because surely I need to call the knex setup for Node to run it?

推荐答案

对于绊脚石的人来说，问题实际上出在db.js上，尤其是最后一行:

For anyone stumbling across this, the problem was actually coming from db.js, specifically the last line:

const config = require('../knexfile.js');
const env = process.env.NODE_ENV || 'development';
const knex = require("knex")(config[env]);

module.exports = knex;

knex.migrate.latest([config]);

当然这是异步的，并且测试在尝试运行自己的knex函数之前会导入该文件，从而导致锁定.为了解决这个问题，我添加了一个子句来阻止它在测试时运行:

Of course this is asynchronous, and the tests were importing this file before trying to run their own knex functions, causing the lock. I got round this by adding a clause to block this running while testing:

if(process.env.NODE_ENV != 'test') {
   knex.migrate.latest([config])
}

然后，您可以通过将process.env.NODE_ENV='test'添加到每个规范文件或安装 npm env测试模块.

You can then create a test environment by adding process.env.NODE_ENV='test' to each spec file, or by installing the npm env test module.

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