Testing Asynchronous Calls With FutureKit

VillainServiceTest.swift

import XCTest
import Nimble

import SwiftyJSON
import FutureKit

@testable import VillainApp

class VillainServiceTest: XCTestCase {
    var service: VillainService!
    var mockSession: MockSession!

    let fakeHTTPResponse = HTTPURLResponse(url: URL(string: "http://www.wearevillains.com/")!,
                                             statusCode: 200, httpVersion: nil, headerFields: nil)!
    override func setUp() {
        super.setUp()
        
        self.continueAfterFailure = false
                
        service = VillainService()
        
        mockSession = MockSession()
        service.session = mockSession
    }
        
    func testGetVillainList() {
        let villainsDict = ["villainCount": 3, 
                            "villains":[
                                ["name": "Cruella DeVille",
                                 "specialty": "unethical treatment of animals"],
                                ["name": "Ursula",
                                 "specialty": "fine print"],
                                ["name": "Elphaba",
                                 "specialty": "faking own death"],
                             ]
                           ]
        
        let villainResponse = VillainResponse.init(fromJSON: JSON(villainsDict))
        let villainData: Data = try! JSONSerialization.data(withJSONObject: villainsDict, options: .prettyPrinted)
        let someResponse = URLResponse(url: URL(string: "http://www.wearevillains.com/")!, mimeType: nil, expectedContentLength: 0, textEncodingName: nil)
        
        let future = self.service.getVillainList()
        
        mockSession.completionHandler!(villainData, someResponse, nil)
        
        future.onSuccess { (successResponse) -> Void in
            expect(self.mockSession.request?.url?.scheme).to(equal("http"))
            expect(self.mockSession.request?.url?.host).to(equal("www.wearevillains.com"))
            expect(self.mockSession.request?.url?.path).to(equal("/team"))
            expect(self.mockSession.request?.httpMethod).to(equal("GET"))
            expect(successResponse).toEventually(equal(villainResponse))
            
            expect(successResponse.login.expand.absoluteString).to(equal("http://www.wearevillains.com/"))
            
            expect(self.mockSession.stubbedDataTask.resumeWasCalled).to(beTrue())
        }
        future.onCancel {
            fail("Should have successfully obtained villains! Cancelled instead.")
        }
        future.onFail { (error) -> Void in
            print(error)
            fail("Should have successfully obtained villains! Failed instead.")
        }
        
        expect(future.isCompleted).to(beTrue())       
    }
}