如何在JavaScript中模拟pg？
如何在JavaScript中模拟pg？
提问于 2015-07-02 18:47:07
我对mock的概念和javascript编程也是新手。我想在javascript程序中模拟pg (postgres模块)。我可以模仿非常简单的场景，但实际上我不能。
这是我的userHandler.js：
var pg = require('pg');
var connectionString = process.env.DATABASE_URL || 'postgres://admin:admin@localhost:5432/mydb';
exports.handlePost = function(req,res){
var results = [];
// Grab data from http request
var adata = [req.body.Username, ..., req.body.FaxNum]; //Ignore for short.
// Get a Postgres client from the connection pool
pg.connect(connectionString, function(err, client, done) {
// SQL Query > Insert Data
var func_ = 'SELECT Dugong.Users_Add($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19)';
var addUser_ = client.query(func_, adata);
addUser_.on('error', function(error){
var data = {success : false,
username : req.body.Username,
reason : {errmsg : error.detail,
errid : 'addUser_' }};
return res.json(data);
});
addUser_.on('end',function(result){
var data = {success : true, username : req.body.Username};
console.log('Insert record completed');
return res.json(data);
});
// Handle Errors
if(err) {
console.log(err);
return ;
}
return;
});
};这是我的单元测试文件。m_users_page.js：
var express = require('express');
var router = express.Router();
var test = require('unit.js');
var mock = require('mock');
var httpMocks = require('node-mocks-http');
var real_users_page = require('../routes/users_page.js');
var b = mock("../routes/userHandler.js", {
pg: {
connect: function (connectionString,callback) {
if(connectionString === 'postgres://admin:admin@localhost:5432/skorplusdb'){
console.log('333');
//pseudo object
var client = {query : function(func_, adata, cb){
cb(null,adata);
}};
client.on('error', 'test emit the error in my mock unit.');
//pseudo done object
var done = function(){};
callback(null, client, done);
return ;
}
}
}
}, require);
describe('Test with static login', function(){
it('Test simple login', function(done){
var request = httpMocks.createRequest({
method: 'POST',
url: '/users',
body: { Username:"Je", ..., FaxAreaCode:'232'} //Ignore for short
});
var response = httpMocks.createResponse();
b.handlePost(request,response, function(){
var data = response._getData();
console.log("7777777777" + data);
done();
});
});
});下面是错误：
$ mocha testing/m_users_page.js
Test with static login
333
1) Test simple login
0 passing (7ms)
1 failing
1) Test with static login Test simple login:
TypeError: Object #<Object> has no method 'on'
at Object.mock.pg.connect (testing/m_users_page.js:22:14)
at Object.exports.handlePost (routes/userHandler.js:30:6)
at Context.<anonymous> (testing/m_users_page.js:63:5)我的问题是：
在Node + Express + Mock + node-mocks-http?
- How中做单元测试的合适方式是什么?要找到好的框架和好的文档，我必须阅读
- 。几天后，我开始在搜索引擎的搜索结果中打转。它们太简单了，我不能使它适应我的问题。
回答 1
Stack Overflow用户
发布于 2018-08-25 07:34:00
首先，确保您理解单元测试和集成测试之间的区别。如果您想对实际的数据库进行测试，即使它有一个虚拟数据集，这也是一个集成测试，它不需要模拟:只需连接到具有虚拟数据的数据库即可。
但是假设你想测试你的the服务器模块，并且你想模拟db。首先，将数据库模块作为参数传递，而不是直接请求pg。另外，使用您自己的类包装postgres接口：
const { Pool } = require('pg');
module.exports = class DatabaseInterop {
// Connection parameters can be passed to the constructor or the connect method, parameters to
// DatabaseInterop::connect will override the initial constructor parameters.
constructor ({
user,
password,
database,
host,
logger={log: console.log, err: console.error},
}) {
this.logger = logger;
this._params = {
user,
password,
database,
host,
};
}
connect (params) {
const {
user,
password,
database,
host,
} = Object.assign({}, this._params, params);
this._pool = new Pool({
user,
password,
database,
host,
});
['SIGHUP', 'SIGINT', 'SIGQUIT', 'SIGILL', 'SIGTRAP', 'SIGABRT',
'SIGBUS', 'SIGFPE', 'SIGUSR1', 'SIGSEGV', 'SIGUSR2', 'SIGTERM'
].forEach(function (sig) {
process.on(sig, async () => {
logger.log(`Exiting for ${sig}...`);
process.exit(0);
});
});
return this;
}
async stop () {
return this._pool.end();
}
runQuery (queryString, params=[]) {
return params.length ? this._pool.query(queryString, params) : this._pool.query(queryString);
}
};现在，为了模拟它，您可以简单地在测试文件中扩展您的自定义类：
const DatabaseInterop = require('/path/to/database_interop.js');
class MockDB extends DatabaseInterop {
connect () {
// no-op
}
runQuery (qs, ...params) {
// return whatever
}
stop () {
// noop
}
}现在，对于您的测试，您可以注入mock，而您的实际系统将注入实际的接口。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/31182449
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