Feature: Heartbeat

As an administrator
I want to visit an endpoint
So that I can confirm the server is responding

Let's add a test to ./test/heartbeat.js for our Heartbeat feature. This resource will get a status from the route /heartbeat and return a 200 Ok status code. Let's write our first integration test using Mocha and SuperTest. First off, create a folder named /test inside your vision folder.

Our test describes heartbeat; it expects the response to have a JSON content type and a status code equal to 200 Ok.

var app = require('../app')
, request = require('supertest');

describe('vision heartbeat api', function(){
  describe('when requesting resource /heartbeat', function(){
    it('should respond with 200', function(done){
      request(app)
      .get('/heartbeat')
      .expect('Content-Type', /json/)
      .expect(200, done);
    });
  });
});

Let's implement the Heartbeat feature; we start by creating a simple Express server, ./lib/express/index.js. We include the express and http modules and create an Express application. We then add an application setting via app.set called port and set it to 3000. We define a /heartbeat route via app.get with which we pass a request handler, function, that takes two parameters: req (request) and res (response). We use the response object to return a JSON response. We create an HTTP server with http.createServer by passing our Express application to it; we listen on port 3000 as defined in our application setting called port. We then export the application with module.exports; exporting the application allows us to test it.

var express = require('express')
  , http = require('http')
  , app = express();

app.set('port', 3000);

app.get('/heartbeat', function(req, res){
  res.json(200, 'OK')
});

http.createServer(app).listen(app.get('port'));
module.exports = app;

We now create ./app.js in the root of our project and export the express module:

module.exports = require('./lib/express');

To run our test, execute the following command:

mocha

You should then receive the response:

1 tests complete (14 ms)

If successful, try running the application by executing this command:

npm start

With the app running, run the following curl command in a new terminal and you can see our heartbeat JSON response return a 200 Ok status code:

curl -i http://127.0.0.1:3000/heartbeat

HTTP/1.1 200 OK
X-Powered-By: Express
Content-Type: application/json; charset=utf-8
Content-Length: 4
Date: Fri, 14 Jun 2013 08:28:50 GMT
Connection: keep-alive