javascript - How to unit test express Router routes -

i'm new node , express , i'm trying unit test routes/controllers. i've separated routes controllers. how go testing routes?

config/express.js

  var app = express();   // middleware, etc   var router = require('../app/router')(app); 

app/router/index.js

  module.exports = function(app) {     app.use('/api/books', require('./routes/books'));   }; 

app/router/routes/books.js

  var controller = require('../../api/controllers/books');   var express = require('express');   var router = express.router();    router.get('/', controller.index);    module.exports = router; 

app/api/controllers/books.js

// example controller exports.index = function(req, res) {     return res.status(200).json('ok'); }; 

app/tests/api/routes/books.test.js

  var chai = require('chai');   var should = chai.should();   var sinon = require('sinon');    describe('bookroute', function() {    }); 

code:

config/express.js

var app = express(); // middleware, etc var router = require('../app/router')(app);  module.exports = app; 

app/tests/api/routes/books.test.js

var chai = require('chai'); var should = chai.should(); var sinon = require('sinon'); var request = require('supertest'); var app = require('config/express');  describe('bookroute', function() {     request(app)         .get('/api/books')         .expect('content-type', /json/)         .expect('content-length', '4')         .expect(200, "ok")         .end(function(err, res){            if (err) throw err;         }); }); 

considerations:

if server requires initial state @ beginning of set of tests (because you're executing calls mutate server state), you'll need write function return freshly configured app , beginning of each group of tests. there npm library: https://github.com/bahmutov/really-need allow require freshly instantiated version of server.