Lab returns error no method 'experiment' - node.js

Question

I am writing the test code for a function that will check for the existence of a username in twitter. I am using the Hapi framework and Lab for testing.
When I run npm test I get the following error:
> NameGen#0.0.0 test /Users/mario/projects/NameGen
> ./node_modules/lab/bin/lab -c
/Users/mario/projects/NameGen/test/test.js:5
Lab.experiment( "Test Username Existence", function() {
^
TypeError: Object #<Object> has no method 'experiment'
at Object.<anonymous> (/Users/mario/projects/NameGen/test/test.js:5:5)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js [as origLoader] (module.js:474:10)
at Object.require.extensions..js (/Users/mario/projects/NameGen/node_modules/lab/lib/coverage.js:32:26)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Module.require (module.js:364:17)
at require (module.js:380:17)
at /Users/mario/projects/NameGen/node_modules/lab/lib/cli.js:85:23
at Array.forEach (native)
at Object.internals.traverse (/Users/mario/projects/NameGen/node_modules/lab/lib/cli.js:81:19)
at Object.exports.run (/Users/mario/projects/NameGen/node_modules/lab/lib/cli.js:30:29)
at Object.<anonymous> (/Users/mario/projects/NameGen/node_modules/lab/bin/lab:3:23)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Function.Module.runMain (module.js:497:10)
at startup (node.js:119:16)
at node.js:906:3
npm ERR! Test failed. See above for more details.
npm ERR! not ok code 0
My test code is:
var Lab = require("lab");
var server = require('../'); // require index.js
var request = require('request');
Lab.experiment( "Test Username Existence", function() {
// tests
Lab.test( "Test username exists", function(done){
var options = {
url: 'http://twitter.com/BarackObama'
};
request(options, function(error, response, body){
Lab.expect(response.statusCode).to.equal(200);
});
done();
});
Lab.test("Test username does not exists", function(done){
var options = {
url: 'http://twitter.com/jhkhksdhkjahsdfkjhasdf'
};
request(options, function(error, response, body){
Lab.expect(response.statusCode).to.equal(404);
});
done();
});
});
I have the latest version of node installed and all the necessary dependencies in my package.json file. What could be causing this error?

Answer 1

As #Jordonias had stated. However, when I used his example, it still did not work.
I had to change the 2nd line to:
lab = exports.lab = Lab.script()

Answer 2

Per the Lab docs: Test files must require the lab module, and export a test script
test.js
var Lab = require('lab');
var lab = module.exports = Lab.script();
lab.experiment( "Test Username Existence", function() {
lab.test( "Test username exists", function(done){
});
});