Testing Asynchronous Calls With FutureKit

VillainsMasterViewControllerTest.swift

import FutureKit
import XCTest
import Nimble

@testable import VillainApp

class VillainsMasterViewControllerTest: XCTestCase {
  
   var viewController: VillainsMasterViewController!
   var mockVillainService: MockVillainService!
   var somePromise: Promise<VillainResponse>?
  
   class MockVillainService: VillainService {
      var stubbedPromise: Promise<VillainResponse>?
     
     
      override func getVillainList() -> Future<VillainResponse> {
        return stubbedPromise.future
      }
   }

   override func setUp() {
        super.setUp()

        somePromise = Promise<VillainResponse>()
        mockVillainService = MockVillainService()
        mockVillainService.stubbedPromise = somePromise
     
    }
  
  ...
  
  func testSuccessfulCallDisplaysVillains() {
        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 villainsResponse = VillainResponse.init(fromJSON: JSON(villainsDict))
    
        villainsController.loadFromStoryboard(mockVillainService)
        assertThat(villainsController.view, present())

        let window = UIWindow()
        window.rootViewController = controller
        window.makeKeyAndVisible()
            
        controller.didTapLoginButton(NSObject())

        expect(self.somePromise?.isCompleted).toNot(beTrue())
        somePromise?.completeWithSuccess(villainsResponse!)
                                                      
        expect(self.somePromise?.isCompleted).to(beTrue())
                                                      
        //assert that the villain list is populated
        window.resignKey()
        window.isHidden = true
    }
    
}