Now that we have Express installed and our package.json file in place, we can begin to drive out our application with a test-first approach. We will now install two modules to assist us: mocha and supertest.

Mocha is a testing framework for node; it's flexible, has good async support, and allows you to run tests in both a TDD and BDD style. It can also be used on both the client and server side. Let's install Mocha with the following command:

npm install -g mocha –-save-dev

SuperTest is an integration testing framework that will allow us to easily write tests against a RESTful HTTP server. Let's install SuperTest:

npm install supertest –-save-dev