Refactor code to testable

Refactor code to testable
Hokila 
Cocoa heads Taipei 2017.11

2
什什麼是 Unit Test
ModuleInput Output

3
現實上的難關
常⾒見見說法
feature 都來來不及做了了，哪有時間寫
我們家有 QA
有 UI Test 啊

4
現實上的難關
實際上
不會寫
Input 無法控制 (API , 不是⾃自⼰己寫的 SDK)
ViewController 超級無敵⼤大

5
Beneﬁt
• 同樣的 code ⽤用兩兩種思考⽅方式看過
• ⾃自然⽽而然學會切 module，或者合併商業邏輯
• ⼀一次跑完幾百個幾千的 check，令⼈人安⼼心
• ⽽而且很快

實際案例例
login View Controller

7
LoginViewController
login API
AccountKit login API
Facebook login API
save Token after login success
tracking event
set User Info

8
問題 - dependency 太多
login API，成功 or 失敗
facebook / AccountKit SDK ⾏行行為
是否有存下 AccessToken
User 資料是不是該有的都有 (UserID , MemberShip)
該有的 tracking 是不是有送
login 時
login 後

拆出 login manager
不知道在幹嘛的 module 叫 manager 就對了了

10
protocol LoginManagerDelegate:class{
func loginStart()
func loginSuccess(status:LoginStatus)
func loginFail(json:[String:Any]?,error:NSError?)
}
class LoginManager{
static let shareInstance = LoginManager()
weak var delegate:LoginManagerDelegate?
func loginFB()
func loginAccountKit()
}

11
class LoginController: BaseViewController{
func touchFBlogin(_ sender: AnyObject) {
self.loginManager.loginFB()
}
func touchAClogin(_ sender: AnyObject){
self.loginManager.loginAccountKit()
}
}
extension LoginController:LoginManagerDelegate{
func loginStart(){ //show indicator }
func loginFail(json:[String:Any]?,error:NSError?){ //error handling}
func loginSuccess(status:LoginStatus){ //success flow }
}

12
LoginViewController LoginManager
login API
Facebook login API
save Token after login success
tracking event
set User Info
login start
login fail handler
login success handler

13
Login
Manager
login API
Facebook login API
LoginManagerDelegate
save Token
tracking event
set User Info

15
模擬 login API ⾏行行為
protocol LoginAPIDelegate {
func loginToken(token:String?,callback:@escaping loginAPICompletion)
}
extension API:LoginAPIDelegate{
func loginToken(token:String?,callback:@escaping loginAPICompletion{
// call real API here
}
}

16
模擬 Facebook SDK response ⾏行行為
protocol FBLoginManagerDelegate {
var currentAccessToken:String? { get }
……
}
class FBLogInManager:FBLoginManagerDelegate {
var currentAccessToken:String? {
return FBSDKAccessToken.current()?.tokenString
}
……
}

17
class LoginManager{
private var loginAPI:LoginAPIDelegate
private let accountKit:AccountKitDelegate
private let fb:FBLoginManagerDelegate
init(api:LoginAPIDelegate = API.shareInstance,
ac:AccountKitDelegate = AKFAccountKit(responseType: .accessToken),
fblogin:FBLoginManagerDelegate = FBLogInManager()) {
self.loginAPI = api
self.accountKit = ac
self.fb = fblogin
}
}
Real Instance

19
class MockLoginAPI:LoginAPIDelegate {
var loginCallback:(LoginStatus,[String:Any]?, AccessToken?, NSError?)
func loginToken(token:String?,callback:@escaping loginAPICompletion {
callback(loginCallback.0,loginCallback.1,
loginCallback.2,loginCallback.3)
}
}
class MockFBLogin:FBLoginManagerDelegate {
var currentAccessToken: String?
}

20
func testFBloginSuccess() {
//1.prepare input
mockFBLogin.currentAccessToken = "123456789"
let loginJSON = loadData(fileName: "loginSuccess", type: "json")
mockLoginAPI.loginCallback = (.loginSuccess,loginJSON,authToken,nil)
//2.Compose Login Manager
self.loginManager = KTLoginManager(api: mockLoginAPI,
ac: mockAC,
fblogin: mockFBLogin)
self.loginManager.delegate = mockLoginVC
//3.trigger login
loginManager.loginFB()
//4.Verify output
……..
}

21
func testFBloginSuccess() {
……..
//4.Verify output
XCTAssertTrue(mockLoginVC.isLoginSuccess)
XCTAssertNotNil(mockAccessTokenManager.lastAccessToken)
XCTAssertEqual(KTUser.shareUser.info.memberShip, .premium)
XCTAssertNotNil(KTUser.shareUser.info.userID)
XCTAssertEqual(mockTracker.lastStatus, .loginSuccess)
XCTAssertEqual(mockTracker.lastLoginType, .facebook)
XCTAssertNotNil(mockTracker.lastLoginUserInfo.userID)
}

dependency injection 問題
inject 的 module 太多，不確定有沒有漏

23
class LoginManager{
private var loginAPI:LoginAPIDelegate
private let accountKit:AccountKitDelegate
private let fb:FBLoginManagerDelegate
init(api:LoginAPIDelegate = API.shareInstance,
ac:AccountKitDelegate = AKFAccountKit(responseType: .accessToken),
fblogin:FBLoginManagerDelegate = FBLogInManager()) {
self.loginAPI = api
self.accountKit = ac
self.fb = fblogin
}
}
Real Instance

24
struct LoginManagerInject{
var loginAPI:KTLoginAPIDelegate = KTAPI.shareInstance
var accountKit:KTAccountKitDelegate = AKFAccountKit(responseType: .accessTok
var fb:KTFBLoginManagerDelegate = FBLogInManager()
}
class LoginManager{
private let inject:LoginManagerInject
init(inject:LoginManagerInject = LoginManagerInject() ){
self.inject = inject
}
}

24
}
class LoginManager{
}
}
self.loginAPI

24
}
class LoginManager{
}
}
self.injec.loginAPIself.loginAPI

26
User
UserInfo
UserSetting
User Info save in memory
Ex:User ID, Member Ship
User Setting save in NSUserDefault
Ex:IsShowXXPage
When UserInfo change , some UserSetting Variable also change
Requirement
AppDelegate

27
class UserInfo {
private var userSetting:UserSettingDelegate
init(userSetting:UserSettingDelegate = shareAppDelegate.user.setting){
self.userSetting = userSetting
}
}
User UserInfoAppDelegat
User UserSettingAppDelegate

28
class UserInfo {
}
}
User
UserSetting
AppDelegate
UserInfo

29
class UserInfo {
}
}
User
UserSetting
AppDelegate
UserInfo
User UserSettingAppDelegate

30
class UserInfo:{
private var injectFunc:()->UserSetting
private var setting:UserSetting {
return self.injectFunc()
}
init(injectFunc:@escaping ()->UserSetting =
{return shareDelegate.user.setting}){
self.injectFunc = injectFunc
}
}

30
class UserInfo:{
}
}
}
stored property

30
class UserInfo:{
}
}
}
stored property
computed property

30
class UserInfo:{
}
}
}
self.setting
stored property
computed property

31
殘酷的事實
花了了⼀一倍的時間寫 Feature，但是邏輯都混在⼀一起沒有拆 module，
要 refactor + 補 Unit Test 的時間，⼤大概就跟原本 Feature 的時間⼀一樣

32
循環
寫了了⼀一個 Feature，但是邏輯都混在⼀一起沒有拆 module
要補 Unit Test 好累喔，要 refactor 好危險
不敢動，不知道怎麼拆 module
有了了新 Request
寫了了⼀一個新Feature，但是邏輯都混在⼀一起沒有拆 module
…………….

33
今天開始寫 Unit Test
• 列列出 priority
• 絕對不可以錯的 module + 會⼤大量量 refuse 的 model
• 下次寫新 module 的時候先想 input output
• 做了了⼀一堆 feature ，User 可能會喜歡可能不會喜歡， 
但是重要功能出 bug，那就死定了了

Refactor code to testable

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