Testing RESTful APIs with Mocha

Have you noted that the app.jsexpress application created with express-generator is actually a node.js module exporting the express instance? In case you have, you must have asked yourself why that is actually needed. Well, having the express instance exported as a module enables it to be unit-tested. We already utilized the mocha framework in Chapter 4, Using NoSQL Databases, where we developed a unit test for the CatalogItem module. We will use mocha once again and wrap a unit test around each operation API exposes. To unit-test the express application, we will need to do the following:

1. Require an instance to the express.js application with the routes, making use of its being exported as a module
2. Start the express.js instance in unit test environment
3. Invoke its operations via a test library and assert against the results
4. Finally, execute the npm test command to trigger the unit test

Before moving on and implementing mocha tests, we need a library for sending...