How should I start my nodejs application automatically for tests - node.js

Question

I have a nodejs restful style service which has no front end, it just accepts data and then does something with it.
I have unit tested most of the method level stuff I want to, however now I want to basically do some automated tests to prove it all works together. When I am using ASP.MVC and IIS its easy as the server is always on, so I just setup the scenario (insert dummy guff into DB) then make a HttpRequest and send it to the server and assert that I get back what I expect.
However there are a few challenges in nodejs as the applications need to be run via command line or some other mechanism, so given that I have an app.js which will start listening, is there some way for me to automatically start that going before I run my tests and then close it once my tests are finished?
I am currently using Yadda with Mocha for my testing so I can keep it written in a BDD style way, however I am hoping the starting of the web app is agnostic of the frameworks I am using.

Answer 1

Just expose some methods to start and stop your webserver. Your app.js file could be something like this:
var app = express()
var server = null
var port = 3000
// configure your app here...
exports.start = function(cb) {
server = http.createServer(app).listen(port, function () {
console.log('Express server listening on port ' + port)
cb && cb()
})
}
exports.close = function(cb) {
if (server) server.close(cb)
}
// when app.js is launched directly
if (module.id === require.main.id) {
exports.start()
}
And then in your tests you can do something like this (mocha based example):
var app = require('../app')
before(function(done) {
app.start(done)
})
after(function(done) {
app.close(done)
})

Answer 2

Have a look to supertest https://github.com/visionmedia/supertest
You can write test like
describe('GET /users', function(){
it('respond with json', function(done){
request(app)
.get('/user')
.set('Accept', 'application/json')
.expect('Content-Type', /json/)
.expect(200, done);
})
})

Answer 3

Using gimenete's answer, here's an example of a service (server) with async await and express:
service.js:
const app = require('express')()
const config = require('./config')
let runningService
async function start() {
return new Promise((resolve, reject) => {
runningService = app.listen(config.get('port'), config.get('hostname'), () => {
console.log(`API Gateway service running at http://${config.get('hostname')}:${config.get('port')}/`)
resolve()
})
})
}
async function close() {
return new Promise((resolve, reject) => {
if (runningService) {
runningService.close(() => {
})
resolve()
}
reject()
})
}
module.exports = {
start,
close
}
service.spec.js:
const service = require('../service')
beforeEach(async () => {
await service.start()
})
afterEach(async () => {
await service.close()
})