Unit Testing HTTP traffic in Alamofire app

Question

I\'m struggling a bit to figure out how to best test an app that uses Alamofire to help sync with server data.

I want to be able to test my code that uses Alamofire

Answer 1

I'm adding another answer since I've just found this approach that in my opinion is easier and really simple to read and use.

I've created a dummy Alamofire class that contains only the functions and the types necessary for tests. Now I include this file in the test target instead of the real Alamofire.

For example I've created my version of the Request class where I define a couple of static variables that I valorise depending on the test, and for this class I've implemented only the init and the responseJSON function.

public class Request {

    var request:String?
    struct response{
        static var data:NSHTTPURLResponse?
        static var json:AnyObject?
        static var error:NSError?
    }

    init (request:String){
        self.request = request
    }

    public func responseJSON(options: NSJSONReadingOptions = .AllowFragments, completionHandler: (NSURLRequest, NSHTTPURLResponse?, AnyObject?, NSError?) -> Void) -> Self {

        completionHandler(NSURLRequest(URL: NSURL(string:self.request!)!), Request.response.data, Request.response.json, Request.response.error)
        return self
    }
}

Now I can mock a response in a test:

func testMytestFunction(){
    var HTMLResponse = NSHTTPURLResponse(URL: NSURL(string: "myurl")!, statusCode: 200, HTTPVersion: "HTTP/1.1", headerFields: nil)

    Request.response.data = HTMLResponse
    Request.response.json = LoadDataFromJSONFile("MyJsonFile")

    request(.POST, "myurl", parameters: nil, encoding: ParameterEncoding.JSON).responseJSON {
        (request, response, JSON, error) -> Void in
        // the JSON and response variable now contains exactly the data that you have passed to Request.response.data and Request.response.json
    }
}

The request function is defined here:

public func request(method: Method, URLString: URLStringConvertible, parameters: [String: AnyObject]? = nil, encoding: ParameterEncoding = .URL) -> Request {

    return Request(request: URLString.URLString)
}

public func request(URLRequest: URLRequestConvertible) -> Request {

    return Request(request: "fakecall")
}