Ajax Design Patterns

Chapter 19. Testing

THANKS TO THE AGILE MOVEMENT, TESTING IS NO LONGER SEEN AS THE BIT AT THE END WHERE QA gives its stamp of approval. It’s a core development technique, and if you’re creating complex web apps, it’s worth testing within and across all tiers.

Because of remoting, Ajax browser scripts usually rely on web services. But it’s not much fun working on both sides at the same time, so Simulation Service explains how to create a “dummy” or “stub” web service to call from the browser. You can use it for tests or for prototyping. Browser-Side Test is simply a test of the JavaScript code sitting in the browser. The hardest thing is to exercise it in an automated fashion; the pattern also looks at that issue. Service Test involves no JavaScript, because it actually takes the place of the browser; an HTTP client is used to test the web service. System Test effectively simulates a user to exercise the application across all layers.

Simulation Service

○ Canned, Double, Dummy, Fake, Masquerade, Mock, Service, Shunt, Sim, Simulation, Stub

Figure 19-1. Simulation Service

Developer Story

Dave is beginning to work on a new email application. Eventually, the server will need to expose a mail API, so the browser can query for recent messages and upload new ones. However, that will require email expertise, and Dave wants to focus on the user interface in the browser for now. Thus, he hardcodes ...