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Async network logic testing using Protocol (Tes...
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Wooseong Kim
December 13, 2017
Programming
2
410
Async network logic testing using Protocol (Test Stub)
presented at Swift Korea meetup (2017/12/13)
Wooseong Kim
December 13, 2017
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Transcript
Wooseong Kim, StyleShare Async network logic testing using Protocol Session
2 #swiftkorea Testing
Problems in networking logic testing Concept - Test Stub Case
study (with Test Stub)
Problems in networking logic testing
None
Want to test here
Want to test here But it’s hard
Because of this!
What if… Offline? Network problem? Server issue? Auth issues?
What if… Offline? Network problem? Server issue? Auth issues?
What if… Offline? Network problem? Server issue? Auth issues?
What if… Offline? Network problem? Server issue? Auth issues?
Offline? Network problem? Server issue? Auth issues? What if…
If the network fails, tests will fail too. What if…
If the network fails, tests will fail too. What if…
Unhappy
Expected Real world →
Expected Solution →
Fake networking?
Fake Networking Request Response Request Response Same response for same
request.
Fake Networking Useful in test environment Production Testing
Called Test Stub Production Testing
So today’s real topic is,
Wooseong Kim, StyleShare #swiftkorea Testing Async network logic testing using
Test Stub Session 2
Case study (with Test Stub)
Case study - Log In
None
None
None
Log-In Button Tap ID/PW Response HTTP Request HTTP Response
Test Stub → ID/PW Response Testing environments Log-In Button Tap
Structures
Production vs Test
Production vs Test Different operation, but same interface
Production vs Test …so they can conform the same protocol!
Production vs Test Difference service on different environment
Codes
protocol AuthServiceType { func logIn(id: String, pw: String, ...) }
protocol AuthServiceType { func logIn(id: String, pw: String, ...) }
// Production class AuthService: AuthServiceType { func logIn(id: String, pw: String, ...) { // Networking logic } }
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 } }
// Production class LogInViewController: UIViewController { var authService: AuthServiceType! ...
} let viewController = LogInViewController() viewController.authService = AuthService() // Test let viewController = LogInViewController() viewController.authService = StubAuthService()
Writing test code with StubAuthService
// Should store the token after logged in class LogInViewController:
UIViewController { ... }
// 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 } } }
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 } }
// Test class StubAuthService: AuthServiceType { func logIn(id: String, pw:
String, completion: (Response) -> Void) { let response = Response(token: "token") // Works synchronously completion(response) } }
// 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! } } }
func testLogIn() { ...? }
func testLogIn() { // given let viewController = LogInViewController() viewController.authService
= StubAuthService() }
func testLogIn() { // given let viewController = LogInViewController() viewController.authService
= StubAuthService() // when viewController.logInButtonDidTap() }
func testLogIn() { // given let viewController = LogInViewController() viewController.authService
= StubAuthService() // when viewController.logInButtonDidTap() // then XCTAssertEqual(viewController.token, "token") }
func testLogIn() { // given let viewController = LogInViewController() viewController.authService
= StubAuthService() // when viewController.logInButtonDidTap() // then XCTAssertEqual(viewController.token, "token") // Failed }
// 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 } } }
// 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 }
Various cases of response - Success or Failure (Wrong password)
class StubAuthService: AuthServiceType { func logIn(id: String, pw: String, completion:
(Response) -> Void) { let response = Response(token: "token") // Success case completion(response) } }
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() { ...? }
class StubAuthService: AuthServiceType { var stubResponse: Response! func logIn(id: String,
pw: String, completion: (Response) -> Void) { completion(stubResponse) } }
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") }
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) }
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) }
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 } } } }
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) }
Stubber
Stubber created by @devxoul Stubber
Stubber is a minimal method stub for Swift.
Stubber is a minimal method stub for Swift. https://github.com/devxoul/Stubber
Summary Tests may fail because of network dependency …so let’s
write test codes with Test Stub May the Test Stub be with you.
Thank you! Wooseong Kim, StyleShare
[email protected]
#swiftkorea