Testing in Swift

Slides for "Testing in Swift" Talk.

Abstract:

Software tests are great for verifying behavior of your software and improving code quality. Jeff will talk about the Swift testing landscape. Learn about tooling and techniques to writing tested code in Swift. We’ll use the Quick testing library to as a basis for discussing good testing practices and common challenges of testing on iOS.

We’ll also explore generative testing, a prevalent functional programming approach to testing and it’s non-functional application.

About Jeff Hui:

Jeff Hui is an iOS software engineer at Pivotal Labs by day. At night, he hacks on open source projects. He’s a core team member of the Cedar and Quick. Besides that, he is the creator of Nimble, Cedar Xcode Plugin, and Fox.

You can find him at jeffhui.net or @jeffhui.

Transcript

1. Testing in Swift Jeff Hui
2. Software Quality
4. Automated programs that describe intent and verify behavior repeatably.
5. Automated programs that describe intent and verify behavior repeatably.
6. Automated programs that describe intent and verify behavior repeatably.
7. Automated programs that describe intent and verify behavior repeatably.
8. Automated programs that describe intent and verify behavior repeatably.
9. XCTest
10. import XCTest class TestSort: XCTestCase { var values: [Int] = [] override func setUp() { values = [2, 5, 3] } func testReorderingOfSmallerIntegersFirst() { sort(&values) XCTAssertEqual(values, [2, 3, 5], "Expected \(values) to equal [2, 3, 5]“) } }
11. Quick BDD Testing Framework
12. import Quick import Nimble class SortSpec: QuickSpec { override func spec() { describe("sorting integers") { var values: [Int] = [] beforeEach { values = [2, 5, 3] } it("reorders smaller integers first in the array") { sort(&values) expect(values).to(equal([2, 3, 5])) } } } }
13. describe("viewing the list of numbers") { it("makes a request for random numbers”) {} it("shows a spinner") {} context("when the service responds with the numbers") { it("hides the spinner") {} it("should display the first number to the user”) {} describe("tapping on the ‘roll’ button”) { it("should add the next random number to the top of the list”) {} } describe("tapping on a randomly generated number") { it("should push the a detail controller on the nav stack”) {} } } }
14. Testing an App
16. Fancy Architecture ListViewController RandomClient DetailViewController
18. ?
19. App Test Bundle
20. App Test Bundle Tests Production
21. App Test Bundle Tests Production Foo
22. App Test Bundle Tests Production Foo
24. XCTest UIApplicationDidFinishLaunchingNotification
25. @UIApplicationMain class DispatchDelegate: UIResponder, UIApplicationDelegate { var window: UIWindow?, appDelegate: AppDelegate! func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { window = UIWindow(frame: UIScreen.mainScreen().bounds) var result = true if isTesting() { window?.rootViewController = UIViewController() } else { appDelegate = AppDelegate(window: window!) result = appDelegate.application(application, didFinishLaunchingWithOptions: launchOptions) } window?.makeKeyAndVisible() return result } private func isTesting() -> Bool { return NSClassFromString("XCTest") != nil } }
26. Testing Networking
27. Testing Networking Nocilla OHHTTPStubs Method Swizzling
28. Adapters
29. public protocol HTTPClient { func sendRequest( request: NSURLRequest, complete: (NSURLResponse?, NSData?, NSError?) -> Void) }
30. public class URLConnectionHTTPClient: HTTPClient { let queue: NSOperationQueue public init() { queue = NSOperationQueue.mainQueue() } public func sendRequest(request: NSURLRequest, complete: (NSURLResponse?, NSData?, NSError?) -> Void) { NSURLConnection.sendAsynchronousRequest(request, queue: queue, completionHandler: complete) } }
31. struct RecordedRequest { let request: NSURLRequest let callback: (NSURLResponse?, NSData?, NSError?) -> Void } class FakeHTTPClient: HTTPClient { var recordedRequests: [RecordedRequest] init() { recordedRequests = [] } func sendRequest(request: NSURLRequest, complete: (NSURLResponse?, NSData?, NSError?) -> Void) { recordedRequests.append(RecordedRequest( request: request, callback: complete)) } }
32. describe("RandomClient") { var client: RandomClient!, fakeHTTPClient: FakeHTTPClient! beforeEach { fakeHTTPClient = FakeHTTPClient() client = RandomClient(httpClient: fakeHTTPClient, apiKey: "my-api-key") } describe("requesting a random number between 0 and 100") { var number: Int?, error: NSError? beforeEach { client.randomInteger { n, err in number = n error = err } } it("should make an HTTP request") { var lastRequest = fakeHTTPClient.recordedRequests.last! expect(lastRequest.request.URL?.absoluteString).to( equal("https://api.random.org/json-rpc/1/invoke")) } // ... } }
33. Adapters
34. Adapters Networking Logging Analytics Persistence
35. UIKit
36. viewController.beginAppearanceTransition( true, animated: false) viewController.endAppearanceTransition()
37. // Swift func tap(barButtonItem: UIBarButtonItem) { SelectorProxy(target: barButtonItem.target). performAction(barButtonItem.action, withObject: barButtonItem) }
38. // Objective-C void tap(UIBarButtonItem *barButtonItem) { id target = barButtonItem.target; SEL action = barButtonItem.action; [target performSelector:action withObject:barButtonItem]; } // Swift func tap(barButtonItem: UIBarButtonItem) { SelectorProxy(target: barButtonItem.target). performAction(barButtonItem.action, withObject: barButtonItem) }
39. func tap(button: UIButton) { button.sendActionsForControlEvents(.TouchUpInside) }
40. func cellAt(tableView: UITableView, indexPath: NSIndexPath) -> UITableViewCell { tableView.layoutIfNeeded() tableView.scrollToRowAtIndexPath(indexPath, atScrollPosition: .Middle, animated: false) return tableView.cellForRowAtIndexPath(indexPath)! }
41. tableView.selectRowAtIndexPath( indexPath, animated: false, scrollPosition: .Middle) tableView.delegate?.tableView?( tableView, didSelectRowAtIndexPath: newIndexPath)
42. github.com/jeffh/TestingInSwift Full Source in Swift 1.2
43. values = [2, 5, 3] sort(&values) expect(values).to(equal([2, 3, 5]))
44. values = [2, 5, 3] sort(&values) expect(values).to(equal([2, 3, 5])) values = [5, 5, 5] sort(&values) expect(values).to(equal([5, 5, 5]))
45. values = [2, 5, 3] sort(&values) expect(values).to(equal([2, 3, 5]))
46. QuickCheck Property Based Testing
47. Fox Property Based Testing
48. Assert(forAll(array(positiveInteger())) { numbers in var nums = customSort(numbers as! [Int]) var n = 0 for i in 0..<nums.count { if n > nums[i] { return false } n = nums[i] } return true })
49. Assert(forAll(array(positiveInteger())) { numbers in var nums = customSort(numbers as! [Int]) var n = 0 for i in 0..<nums.count { if n > nums[i] { return false } n = nums[i] } return true }) func customSort<T: Comparable>(array: [T]) -> [T] { var items = sorted(array) if items.count == 3 { let t = items[0] items[0] = items[2] items[2] = t } return items }
51. [0, 1, 2, 3, 4] [4] [9, 92, 44, 22] [22, 10, 5]
52. [22, 10, 5] [0, 10, 5] [0, 0, 5] [0, 0, 0] [ ] [22, 10] [0, 0, 3] [0, 0, 1]
53. Assert(forAll(array(positiveInteger())) { numbers in var nums = customSort(numbers as! [Int]) var n = 0 for i in 0..<nums.count { if n > nums[i] { return false } n = nums[i] } return true }) failed - Property failed with: (0, 0, 1)
54. State
55. State Can you describe state as values?
56. State Machine
58. Model State Transitions
59. Model State Tran User-state In Memory
60. Model State Tran Active Requests Received Numbers User-state In Memory
61. te Transitions uests mbers precondition acting on the subject model state change postcondition (assertions)
62. te Transitions uests mbers Roll Resolve Request precondition acting on the subject model state change postcondition (assertions)
63. te Transitions uests mbers Roll Resolve Request No precondition Tapping button Add active request Is spinner visible?
64. te Transitions uests mbers Roll Resolve Request At least one active request Resolve HTTP Response Remove active request Is spinner visible?
66. Roll Resolve Roll Roll Resolve
67. Roll Resolve Roll
68. QuickCheck Parallel Testing Asynchronous Testing
69. Questions? @jeffhui jeffhui.net github.com/Quick/Quick github.com/jeffh/TestingInSwift github.com/jeffh/Fox github.com/luisobo/Nocilla github.com/AliSoftware/OHHTTPStubs