Lately I’ve found myself writing asynchronous network calls on mobile platforms in the reactive style. I want to share how you can test-drive calls like this for iOS. The following example uses SwiftyJSON for JSON deseriaization and FutureKit as the asynchronous framework surrounding the network call. There are several libraries in iOS that do both of these things, but your structure here will look similar with any of them.
This example is updated to Swift 3.