Mocha Test: Uncaught TypeError: Cannot read property 'status' of null

Question

Learning TDD and my first simple test for my "Hello World" server response is failing in Mocha. I'm using Mocha.js, Superagent, & Expect.js.

When I curl -i localhost:8080, I get the correct response and status code.

HTTP/1.1 200 OK
Content-Type: text/plain
Date: Mon, 27 Apr 2015 17:55:36 GMT
Connection: keep-alive
Transfer-Encoding: chunked

Hello World

Test code:

var request = require('superagent');
var expect = require('expect.js');

// Test structure
describe('Suite one', function(){
    it("should get a response that contains World",function(done){
        request.get('localhost:8080').end(function(res){
            // TODO check that response is okay
            expect(res).to.exist;
            expect(res.status).to.equal(200);
            expect(res.body).to.contain('World');
            done();
        });
    });
});

Server code:

var server = require('http').createServer(function(req, res){
    res.writeHead(200, {"Content-Type":"text/plain"});
    res.end('Hello World\n');
});

server.listen(8080, function(){
    console.log("Server listening at port 8080");
});

Mocha output:

  Suite one
    1) should get a response that contains World


  0 passing (110ms)
  1 failing

  1) Suite one should get a response that contains World:
     Uncaught TypeError: Cannot read property 'status' of null
      at test.js:10:23
      at _stream_readable.js:908:16

I've tried googling this issue but no luck finding out what I'm doing wrong.

Answer 1

Node notation of callbacks is to have first parameter error.

Superagent is following this Node policy. This is from superagent github site:

request
  .post('/api/pet')
  .send({ name: 'Manny', species: 'cat' })
  .set('X-API-Key', 'foobar')
  .set('Accept', 'application/json')
  .end(function(err, res){
    // Calling the end function will send the request
  });

So change this line

request.get('localhost:8080').end(function(res){

to

request.get('localhost:8080').end(function(err, res){