Async network logic testing using Protocol (Test Stub)

presented at Swift Korea meetup (2017/12/13)

Transcript

1. Wooseong Kim, StyleShare Async network logic testing using Protocol Session 2 #swiftkorea Testing
2. Problems in networking logic testing Concept - Test Stub Case study (with Test Stub)
3. Problems in networking logic testing
5. Want to test here
6. Want to test here But it’s hard
7. Because of this!
8. What if… Offline? Network problem? Server issue? Auth issues?
9. What if… Offline? Network problem? Server issue? Auth issues?
10. What if… Offline? Network problem? Server issue? Auth issues?
11. What if… Offline? Network problem? Server issue? Auth issues?
12. Offline? Network problem? Server issue? Auth issues? What if…
13. If the network fails, tests will fail too. What if…
14. If the network fails, tests will fail too. What if… Unhappy
15. Expected Real world →
16. Expected Solution →
17. Fake networking?
18. Fake Networking Request Response Request Response Same response for same request.
19. Fake Networking Useful in test environment Production Testing
20. Called Test Stub Production Testing
21. So today’s real topic is,
22. Wooseong Kim, StyleShare #swiftkorea Testing Async network logic testing using Test Stub Session 2
23. Case study (with Test Stub)
24. Case study - Log In
28. Log-In Button Tap ID/PW Response HTTP Request HTTP Response
29. Test Stub → ID/PW Response Testing environments Log-In Button Tap
30. Structures
31. Production vs Test
32. Production vs Test Different operation, but same interface
33. Production vs Test …so they can conform the same protocol!
34. Production vs Test Difference service on different environment
35. Codes
36. protocol AuthServiceType { func logIn(id: String, pw: String, ...) }
37. protocol AuthServiceType { func logIn(id: String, pw: String, ...) } // Production class AuthService: AuthServiceType { func logIn(id: String, pw: String, ...) { // Networking logic } }
38. protocol AuthServiceType { func logIn(id: String, pw: String, ...) } // Production class AuthService: AuthServiceType { func logIn(id: String, pw: String, ...) { // Networking logic } } // Test class StubAuthService: AuthServiceType { func logIn(id: String, pw: String, ...) { // Stub logic } }
39. // Production class LogInViewController: UIViewController { var authService: AuthServiceType! ... } let viewController = LogInViewController() viewController.authService = AuthService() // Test let viewController = LogInViewController() viewController.authService = StubAuthService()
40. Writing test code with StubAuthService
41. // Should store the token after logged in class LogInViewController: UIViewController { ... }
42. // Should store the token after logged in class LogInViewController: UIViewController { var authService: AuthServiceType! func logInButtonDidTap() { authService.logIn(id: "id", pw: "pw", completion: { response in // Completion logic } } }
43. protocol AuthServiceType { func logIn(id: String, pw: String, completion: (Response) -> Void) } // Production class AuthService: AuthServiceType { func logIn(id: String, pw: String, completion: (Response) -> Void) { // Networking logic } } // Test class StubAuthService: AuthServiceType { func logIn(id: String, pw: String, completion: (Response) -> Void) { // Stub logic } }
44. // Test class StubAuthService: AuthServiceType { func logIn(id: String, pw: String, completion: (Response) -> Void) { let response = Response(token: "token") // Works synchronously completion(response) } }
45. // Test class StubAuthService: AuthServiceType { func logIn(id: String, pw: String, completion: (Response) -> Void) { let response = Response(token: "token") completion(response) } } // Production class LogInViewController: UIViewController { func logInButtonDidTap() { authService.logIn(id: "id", pw: "pw", completion: { response in // Passed to here! } } }
46. func testLogIn() { ...? }
47. func testLogIn() { // given let viewController = LogInViewController() viewController.authService = StubAuthService() }
48. func testLogIn() { // given let viewController = LogInViewController() viewController.authService = StubAuthService() // when viewController.logInButtonDidTap() }
49. func testLogIn() { // given let viewController = LogInViewController() viewController.authService = StubAuthService() // when viewController.logInButtonDidTap() // then XCTAssertEqual(viewController.token, "token") }
50. func testLogIn() { // given let viewController = LogInViewController() viewController.authService = StubAuthService() // when viewController.logInButtonDidTap() // then XCTAssertEqual(viewController.token, "token") // Failed }
51. // Production class LogInViewController: UIViewController { var authService: AuthServiceType! var token: String func logInButtonDidTap() { authService.logIn(id: "id", pw: "pw", completion: { response in self.token = response.token } } }
52. // Production class LogInViewController: UIViewController { var authService: AuthServiceType! var token: String func logInButtonDidTap() { authService.logIn(id: "id", pw: "pw", completion: { response in self.token = response.token } } } // Test func testLogIn() { ... XCTAssertEqual(viewController.token, "token") // Succeeded }
53. Various cases of response - Success or Failure (Wrong password)
54. class StubAuthService: AuthServiceType { func logIn(id: String, pw: String, completion: (Response) -> Void) { let response = Response(token: "token") // Success case completion(response) } }
55. class StubAuthService: AuthServiceType { func logIn(id: String, pw: String, completion: (Response) -> Void) { let response = Response(token: "token") // Success case completion(response) } } func testLogIn_success() { ... XCTAssertEqual(viewController.token, "token") } func testLogIn_wrongPassword() { ...? }
56. class StubAuthService: AuthServiceType { var stubResponse: Response! func logIn(id: String, pw: String, completion: (Response) -> Void) { completion(stubResponse) } }
57. class StubAuthService: AuthServiceType { var stubResponse: Response! func logIn(id: String, pw: String, completion: (Response) -> Void) { completion(stubResponse) } } func testLogIn_success() { let authService = StubAuthService() authService.stubResponse = Response(token: "token") ... viewController.logInButtonDidTap() XCTAssertEqual(viewController.token, "token") }
58. class StubAuthService: AuthServiceType { var stubResponse: Response! func logIn(id: String, pw: String, completion: (Response) -> Void) { completion(stubResponse) } } func testLogIn_success() { ... } func testLogIn_wrongPassword() { let authService = StubAuthService() authService.stubResponse = Response(error: LogInError.wrongPassword) ... viewController.logInButtonDidTap() XCTAssertEqual(viewController.logInError, LogInError.wrongPassword) }
59. class StubAuthService: AuthServiceType { var stubResponse: Response! func logIn(id: String, pw: String, completion: (Response) -> Void) { completion(stubResponse) } } func testLogIn_success() { ... } func testLogIn_wrongPassword() { let authService = StubAuthService() authService.stubResponse = Response(error: LogInError.wrongPassword) ... viewController.logInButtonDidTap() XCTAssertEqual(viewController.logInError, LogInError.wrongPassword) }
60. enum LogInError { case wrongPassword case idNotExist } class LogInViewController: UIViewController { var authService: AuthServiceType! var token: String var logInError: LogInError func logInButtonDidTap() { authService.logIn(id: "id", pw: "pw", completion: { response in if response.status == .success { self.token = response.token } else if response.status == .failure { self.logInError = response.error } } } }
61. enum LogInError { case wrongPassword case idNotExist } class LogInViewController: UIViewController { var authService: AuthServiceType! var token: String var logInError: LogInError func logInButtonDidTap() { authService.logIn(id: "id", pw: "pw", completion: { response in if response.status == .success { self.token = response.token } else if response.status == .failure { self.logInError = response.error } } } } func testLogIn_wrongPassword() { ... // Succeeded XCTAssertEqual(viewController.logInError, LogInError.wrongPassword) }
62. Stubber
63. Stubber created by @devxoul Stubber
64. Stubber is a minimal method stub for Swift.
65. Stubber is a minimal method stub for Swift. https://github.com/devxoul/Stubber
66. Summary Tests may fail because of network dependency …so let’s write test codes with Test Stub May the Test Stub be with you.
67. Thank you! Wooseong Kim, StyleShare innocarpe@gmail.com #swiftkorea