Now that we have a basic test infrastructure, we'll turn our attention toward integrating a Backbone.js application and mapping out a test development strategy. In this chapter, we will create a test plan by working through the following topics:
- Reviewing some fundamental concepts of Backbone.js development
- Selecting a Backbone.js application to test
- Examining relevant testing concepts and approaches to guide test plan creation and execution
- Evaluating parts of the Backbone.js application to test in complete or partial isolation
- Identifying tests that exercise multiple interacting parts of the Backbone.js application
- Integrating the Backbone.js application into our test infrastructure, and authoring and running a few introductory application tests
Although this book assumes a comfortable level of familiarity with Backbone.js, Underscore.js, and jQuery, we will briefly touch upon the basics of Backbone.js application development.
Backbone.js provides abstractions and useful functionality for architecting and developing JavaScript web applications. Backbone.js brings order to the chaotic interactions between program and display logic, DOM events, and backend communication. This is achieved via what could loosely be considered a Model-View-Controller (MVC) paradigm that separates application code into the following topics:
- Data modeling and retrieval
- Display rendering and user interactivity
- Brokering data and display logic to appropriately bind and manipulate data models and user interfaces
Note
Backbone.js does not completely follow a traditional MVC approach, causing some observers to call it an MV* framework. An MV* application has a model and a view but has something other than a controller connecting the model and the view. For a much more detailed discussion on MVC and the various MV* approaches, see Developing Backbone.js Applications by Addy Osmani, and the article, Journey Through The JavaScript MVC Jungle (http://coding.smashingmagazine.com/2012/07/27/journey-through-the-javascript-mvc-jungle/).
To this end, Backbone.js provides a set of core library components:
- Events: The
Backbone.Eventsmodule gives JavaScript objects the ability to emit and respond to events, including built-in Backbone.js class events as well as custom application events. - Models: The
Backbone.Modelclass provides a data wrapper that can synchronize with a backend, validate data changes, and emit events to other parts of a Backbone.js application. A model is the fundamental unit of data in a Backbone.js application. - Collections: The
Backbone.Collectionclass wraps a set of models in an ordered list. Collections provide events, backend synchronization, and many helper methods for manipulating and mutating the set of underlying models. - Templates: Backbone.js leaves the choice of the template library up to the developer (we will use Underscore.js templates for this book). Other popular template alternatives include Handlebars (http://handlebarsjs.com/), Mustache (https://github.com/janl/mustache.js/), and EJS (http://embeddedjs.com/).
- Views: A
Backbone.Viewobject is the glue that binds models, collections, and templates together with the browser environment and DOM. Backbone.js is deliberately agnostic as to what a view must do, but a typical view references a collection or a model, couples data to the user interface via a template, and mediates user interaction and backend server events. To clarify potentially confusing terminologies,Backbone.Viewis much more analogous to a traditional MVC controller, and a Backbone.js template acts like an MVC view. - Routers: Backbone.js programs are commonly developed as single-page applications in which the entire HTML page source and JavaScript libraries are downloaded in a single page load.
Backbone.Routermaintains the internal state of the application and manages the browser history. Routers provide client-side routing via URL hash fragments (#app-page) to allow different views to be linked to, bookmarked, and navigated like traditional web pages.
In the chapters that follow, we will test these components separately and together, so it is important to ensure a solid grasp of the fundamentals. The core documentation at http://backbonejs.org is a good starting point for the concepts, API, and pointers and tips on application development. For a deeper dive into Backbone.js topics, there are many great online and print resources, including:
- Developing Backbone.js Applications by Addy Osmani, which is a Creative-Commons-licensed book developed with the help of the open source community on GitHub. This book discusses the theory, architecture, and fundamentals of creating Backbone.js applications (https://github.com/addyosmani/backbone-fundamentals).
- Derick Bailey's Blog, which is a blog that is frequently updated with many Backbone.js posts and has been written by the creator of
Backbone.Marionette(http://lostechies.com/derickbailey/category/backbone/). - The official Backbone.js wiki page that aggregates blog posts, tutorials, and working examples (https://github.com/documentcloud/backbone/wiki/Tutorials%2C-blog-posts-and-example-sites).