Devising and implementing a test plan is fundamentally a practical exercise, and we can better achieve our goal of overall application reliability by applying test lessons and techniques to a real application—whether it is one that has just been started or an existing application in need of better test coverage.

If you already have a Backbone.js application in development, you can most likely skip to the next section of this chapter. One potential issue we want to identify is the complexity of the existing application, especially one with minimal or no existing tests. Complicated dependencies, non-modular design, and highly coupled application components may require extensive mocking and stubbing to even permit a base level of test framework integration. Ultimately, the test infrastructure written around a legacy application will likely be quite different from the one written around a modular, decoupled application such as Notes. Accordingly, you...