How to unit test asynchronous APIs?

Question

I have installed Google Toolbox for Mac into Xcode and followed the instructions to set up unit testing found here.

It all works great, and I can test my synchronous

Answer 1

If you're using a library such as AFNetworking or ASIHTTPRequest and have your requests managed via a NSOperation (or subclass with those libraries) then it's easy to test them against a test/dev server with an NSOperationQueue:

In test:

// create request operation

NSOperationQueue* queue = [[NSOperationQueue alloc] init];
[queue addOperation:request];
[queue waitUntilAllOperationsAreFinished];

// verify response

This essentially runs a runloop until the operation has completed, allowing all callbacks to occur on background threads as they normally would.