The starting point for the Notes application is a namespace utility that provides two global variables to organize our application classes (App) and instance (app). In the notes/app/js/app/namespace.js example application file, we'll create the two namespace object literals with class/application properties:

// Class names.
var App = App   || {};
App.Config      || (App.Config = {});
App.Models      || (App.Models = {});
App.Collections || (App.Collections = {});
App.Routers     || (App.Routers = {});
App.Views       || (App.Views = {});
App.Templates   || (App.Templates = {});

// Application instance.
var app = app || {};

The behavior that we want to test of these helper objects is if they contain the correct properties that other application components will rely upon. Accordingly, the chapters/02/test/js/spec/namespace.spec.js test file just needs a few specs to cover these objects. The first spec provides the 'App' object asserts that App is a JavaScript object with properties for all of the different grouping names (Models, Views, and so on) that we have attached:

describe('Namespace', function () {
  it("provides the 'App' object", function () {
    // Expect exists and is an object.
    expect(App).to.be.an("object");

    // Expect all namespace properties are present.
    expect(App).to.include.keys(
      "Config", "Collections", "Models",
      "Routers", "Templates", "Views"
    );
  });

The second spec provides the 'app' object just checks that the global app variable exists as an object:

  it("provides the 'app' object", function () {
    expect(app).to.be.an("object");
  });
});

Moving on to the actual Backbone.js classes, we will start with the model notes/app/js/app/models/note.js file that provides the data backing a single note in the Notes application:

App.Models.Note = Backbone.Model.extend({
  defaults: function () {
    return {
      title: "",
      text: "*Edit your note!*",
      createdAt: new Date()
    };
  }
});

The model has three fields: title, text, and createdAt. As our example Notes application uses localStorage configured in the collection class, we do not have to provide backend synchronization declarations (for example, a urlRoot property or a url function) to persist model data. Because our model essentially comprises a single defaults declaration, the behavior that we need to test is simply that the default and modified attributes work as expected.

Our test file for the model, chapters/02/test/js/spec/models/note.spec.js, has two specs. The first spec creates an App.Models.Note object with default values and uses get()to verify each attribute:

describe("App.Models.Note", function () {
  it("has default values", function () {
    // Create empty note model.
    var model = new App.Models.Note();

    expect(model).to.be.ok;
    expect(model.get("title")).to.equal("");
    expect(model.get("text")).to.equal("*Edit your note!*");
    expect(model.get("createdAt")).to.be.a("Date");
  });

The second spec sets passed attributes tests a model created with the supplied values for title and text:

  it("sets passed attributes", function () {
    var model = new App.Models.Note({
      title: "Grocery List",
      text: "* Milk
* Eggs
*Coffee"
    });

    expect(model.get("title")).to.equal("Grocery List");
    expect(model.get("text")).to.equal("* Milk
* Eggs
*Coffee");
  });
});