UnitTesting 单元测试

1. 测试分为两种及详细介绍测试书籍:

  1.1 Unit Test : 单元测试

  - test the business logic in your app : 测试应用中的业务逻辑

  1.2 UI  Test :  界面测试

  - test the UI of your app : 测试应用中的界面

  1.3 测试书籍网址:《Testing Swift》 https://www.hackingwithswift.com/store/testing-swift

2. ViewModel 单元测试

  2.1 创建 ViewModel，UnitTestingBootcampViewModel.swift

import Foundation
import SwiftUI
import Combine/// 单元测试 ViewModel
class UnitTestingBootcampViewModel: ObservableObject{@Published var isPremium: Bool@Published var dataArray: [String] = []@Published var selectedItem: String? = nillet dataService: NewDataServiceProtocolvar cancellable = Set<AnyCancellable>()init(isPremium: Bool, dataService: NewDataServiceProtocol = NewMockDataService(items: nil)) {self.isPremium = isPremiumself.dataService = dataService}/// 添加子项func addItem(item: String){// 为空不往下执行guard !item.isEmpty else { return }self.dataArray.append(item)}/// 选中项func selectItem(item: String){if let x = dataArray.first(where: {$0 == item}){selectedItem = x}else{selectedItem = nil}}/// 保存项func saveItem(item: String) throws{guard !item.isEmpty else{throw DataError.noData}if let x = dataArray.first(where: {$0 == item}){print("Save item here!!! \(x)")} else {throw DataError.itemNotFound}}/// 错误信息enum DataError: LocalizedError{case noDatacase itemNotFound}/// 请求返回数据func downloadWithEscaping() {dataService.downloadItemsWithEscaping { [weak self] returnedItems inself?.dataArray = returnedItems}}/// 下载用到的组合func downloadWithCombine() {dataService.downloadItemsWithCombine().sink { _ in} receiveValue: { [weak self] returnedItems inself?.dataArray = returnedItems}.store(in: &cancellable)}
}

  2.2 创建测试文件

    当创建项目时，没有选择 Include Tests/包含测试 选项时，需要添加文件去对应项目，不然测试文件会报 No such module 'XCTest' 编译错误

    添加单元测试文件:

    方法一 : 选择项目 -> 菜单栏 Editor -> Add Target... -> 弹出对话框，选择 Test 栏下 -> Unit Testing Bundle -> 填写信息/可默认 -> Finish，完成创建单元测试文件。

    方法二 : 选择项目，点击 PROJECT 列，最下的 + 按钮，弹出对话框，选择 Test 栏下 ，后面步骤与上一致

    创建单元测试文件 UnitTestingBootcampViewModel_Tests.swift

import XCTest
import Combine
/// 导入项目
@testable import SwiftfulThinkingAdvancedLearning// 《Testing Swift》 测试书籍
// 书籍网址: https://www.hackingwithswift.com/store/testing-swift
// Naming Structure: test_UnitOfWork_StateUnderTest_ExpectedBehavior -  结构体命名: 测试_工作单元_测试状态_预期的行为
// Naming Structure: test_[struct or class]_[variable or function]_[expected result] - 测试_[结构体 或者 类的名称]_[类中的变量名 或者 函数名称]_[预期结果 预期值]
// Testing Structure: Given, When, Then - 测试结构: 给定，什么时候，然后final class UnitTestingBootcampViewModel_Tests: XCTestCase {/// 解决多次引用相同的类var viewModel: UnitTestingBootcampViewModel?var cancellables = Set<AnyCancellable>()/// 开始设置数据override func setUpWithError() throws {// Put setup code here. This method is called before the invocation of each test method in the class.viewModel = UnitTestingBootcampViewModel(isPremium: Bool.random())}/// 结束重置数据override func tearDownWithError() throws {// Put teardown code here. This method is called after the invocation of each test method in the class.viewModel = nilcancellables.removeAll()}/// 单元测试函数名，根据命名规则命名：测试_类名称_是否高质量_应该为真func test_UnitTestingBootcampViewModel_isPremium_shouldBeTrue(){// Givenlet userIsPremium: Bool = true// Whenlet vm = UnitTestingBootcampViewModel(isPremium: userIsPremium)// ThenXCTAssertTrue(vm.isPremium)}/// 单元测试函数名 根据命名规则命名：测试_类名称_是否高质量_应该为假func test_UnitTestingBootcampViewModel_isPremium_shouldBeFalse(){// Givenlet userIsPremium: Bool = false// Whenlet vm = UnitTestingBootcampViewModel(isPremium: userIsPremium)// ThenXCTAssertFalse(vm.isPremium)}/// 单元测试函数名 根据命名规则命名：测试_类名称_是否高品质_注入值func test_UnitTestingBootcampViewModel_isPremium_shouldBeInjectedValue(){// Givenlet userIsPremium: Bool = Bool.random()// Whenlet vm = UnitTestingBootcampViewModel(isPremium: userIsPremium)// ThenXCTAssertEqual(vm.isPremium, userIsPremium)}/// 单元测试函数名 根据命名规则命名 - 注入值_压力 / for 循环func test_UnitTestingBootcampViewModel_isPremium_shouldBeInjectedValue_stress(){for _ in 0 ..< 10 {// Givenlet userIsPremium: Bool = Bool.random()// Whenlet vm = UnitTestingBootcampViewModel(isPremium: userIsPremium)// ThenXCTAssertEqual(vm.isPremium, userIsPremium)}}/// 单元测试函数名 根据命名规则命名 - 数组_预期值：为空func test_UnitTestingBootcampViewModel_dataArray_shouldBeEmpty(){// Given// Whenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Then 断言 = 判定XCTAssertTrue(vm.dataArray.isEmpty)XCTAssertEqual(vm.dataArray.count, 0)}/// 单元测试函数名 根据命名规则命名 - 数组_预期值：添加项func test_UnitTestingBootcampViewModel_dataArray_shouldAddItems(){// Givenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Whenlet loopCount: Int = Int.random(in: 1..<100)for _ in 0 ..< loopCount{vm.addItem(item: UUID().uuidString)}// Then 断言 = 判定XCTAssertTrue(!vm.dataArray.isEmpty)XCTAssertFalse(vm.dataArray.isEmpty)XCTAssertEqual(vm.dataArray.count, loopCount)XCTAssertNotEqual(vm.dataArray.count, 0)// GreaterThan 大于XCTAssertGreaterThan(vm.dataArray.count, 0)// XCTAssertGreaterThanOrEqual// XCTAssertLessThan// XCTAssertLessThanOrEqual}/// 单元测试函数名 根据命名规则命名 - 数组_预期值：添加空白字符func test_UnitTestingBootcampViewModel_dataArray_shouldNotAddBlankString(){// Givenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Whenvm.addItem(item: "")// Then 断言 = 判定XCTAssertTrue(vm.dataArray.isEmpty)}/// 单元测试函数名 根据命名规则命名 - 数组_预期值：添加空白字符func test_UnitTestingBootcampViewModel_dataArray_shouldNotAddBlankString2(){// Givenguard let vm = viewModel else {XCTFail()return}// Whenvm.addItem(item: "")// Then 断言 = 判定XCTAssertTrue(vm.dataArray.isEmpty)}/// 单元测试函数名 根据命名规则命名 - 选中项_预期值：开始为空func test_UnitTestingBootcampViewModel_selectedItem_shouldStartAsNil(){// Given// Whenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Then 断言 = 判定XCTAssertTrue(vm.selectedItem == nil)XCTAssertNil(vm.selectedItem)}/// 单元测试函数名 根据命名规则命名 - 选中项_预期值：应该为空 当选择无效项func test_UnitTestingBootcampViewModel_selectedItem_shouldBeNilWhenSelectingInvalidItem(){// Givenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Select valid item : 选择有效项let newItem = UUID().uuidStringvm.addItem(item: newItem)vm.selectItem(item: newItem)// Select invalid item : 选择无效项// Whenvm.selectItem(item: UUID().uuidString)// Then 断言 = 判定XCTAssertNil(vm.selectedItem)}/// 单元测试函数名 根据命名规则命名 - 选中项_预期值：应该选中func test_UnitTestingBootcampViewModel_selectedItem_shouldBeSelected(){// Givenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Whenlet newItem = UUID().uuidStringvm.addItem(item: newItem)vm.selectItem(item: newItem)// Then 断言 = 判定XCTAssertNotNil(vm.selectedItem)XCTAssertEqual(vm.selectedItem, newItem)}/// 单元测试函数名 根据命名规则命名 - 选中项_预期值：选中_压力测试func test_UnitTestingBootcampViewModel_selectedItem_shouldBeSelected_stress(){// Givenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Whenlet loopCount: Int = Int.random(in: 1..<100)var itemsArray: [String] = []for _ in 0 ..< loopCount {let newItem = UUID().uuidStringvm.addItem(item: newItem)itemsArray.append(newItem)}// 随机取一个字符串let randomItem = itemsArray.randomElement() ?? ""// 检查字符串不为空XCTAssertFalse(randomItem.isEmpty)vm.selectItem(item: randomItem)// Then 断言 = 判定XCTAssertNotNil(vm.selectedItem)XCTAssertEqual(vm.selectedItem, randomItem)}/// 单元测试函数名 根据命名规则命名 - 保存项_预期值：输出错误异常_元素没找到func test_UnitTestingBootcampViewModel_saveItem_shouldThrowError_itemNotFound(){// Givenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Whenlet loopCount: Int = Int.random(in: 1..<100)for _ in 0 ..< loopCount {vm.addItem(item: UUID().uuidString)}// Then 断言 = 判定XCTAssertThrowsError(try vm.saveItem(item: UUID().uuidString))XCTAssertThrowsError(try vm.saveItem(item: UUID().uuidString), "Should throw Item Not Found error!") { error in// 返回错误let returnedError = error as? UnitTestingBootcampViewModel.DataError// 判断错误是否相同XCTAssertEqual(returnedError, UnitTestingBootcampViewModel.DataError.itemNotFound)}}/// 单元测试函数名 根据命名规则命名 - 保存项_预期值：输出错误异常_没数据func test_UnitTestingBootcampViewModel_saveItem_shouldThrowError_noData(){// Givenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Whenlet loopCount: Int = Int.random(in: 1..<100)for _ in 0 ..< loopCount {vm.addItem(item: UUID().uuidString)}// Then 断言 = 判定do {try vm.saveItem(item: "")} catch let error {// 返回错误let returnedError = error as? UnitTestingBootcampViewModel.DataError// 判断错误是否相同XCTAssertEqual(returnedError, UnitTestingBootcampViewModel.DataError.noData)}}/// 单元测试函数名 根据命名规则命名 - 保存项_预期值：保存选项func test_UnitTestingBootcampViewModel_saveItem_shouldSaveItem(){// Givenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Whenlet loopCount: Int = Int.random(in: 1..<100)var itemsArray: [String] = []for _ in 0 ..< loopCount {let newItem = UUID().uuidStringvm.addItem(item: newItem)itemsArray.append(newItem)}// 随机取一个字符串let randomItem = itemsArray.randomElement() ?? ""// 检查字符串不为空XCTAssertFalse(randomItem.isEmpty)// Then 断言 = 判定XCTAssertNoThrow(try vm.saveItem(item: randomItem))do {try vm.saveItem(item: randomItem)} catch  {XCTFail()}}/// 单元测试函数名 根据命名规则命名 - 下载数据_预期值：返回选项func test_UnitTestingBootcampViewModel_downloadWithEscaping_shouldReturnItems(){// Givenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Whenlet expectation = XCTestExpectation(description: "Should return items after 3 seconds")// dropFirst: 删除第一个发布 数组值，因为初始化为空数组，取的是第二个数组，模拟服务数据返回的数组vm.$dataArray.dropFirst().sink { returnedItems inexpectation.fulfill()}.store(in: &cancellables)vm.downloadWithEscaping()// Then 断言 = 判定 GreaterThan：大于// 为了安全获取到值，设置等待 5 秒wait(for: [expectation], timeout: 5)XCTAssertGreaterThan(vm.dataArray.count, 0)}/// 单元测试函数名 根据命名规则命名 - 下载数据组合_预期值：返回选项func test_UnitTestingBootcampViewModel_downloadWithCombine_shouldReturnItems(){// Givenlet vm = UnitTestingBootcampViewModel(isPremium: Bool.random())// Whenlet expectation = XCTestExpectation(description: "Should return items after a seconds")// dropFirst: 删除第一个发布 数组值，因为初始化为空数组，取的是第二个数组，模拟服务数据返回的数组vm.$dataArray.dropFirst().sink { returnedItems inexpectation.fulfill()}.store(in: &cancellables)vm.downloadWithCombine()// Then 断言 = 判定 GreaterThan：大于// 为了安全获取到值，设置等待 5 秒wait(for: [expectation], timeout: 5)XCTAssertGreaterThan(vm.dataArray.count, 0)}/// 单元测试函数名 根据命名规则命名 - 下载数据组合_预期值：返回选项func test_UnitTestingBootcampViewModel_downloadWithCombine_shouldReturnItems2(){// Givenlet items: [String] = [UUID().uuidString, UUID().uuidString, UUID().uuidString, UUID().uuidString]let dataService: NewDataServiceProtocol = NewMockDataService(items: items)let vm = UnitTestingBootcampViewModel(isPremium: Bool.random(), dataService: dataService)// Whenlet expectation = XCTestExpectation(description: "Should return items after a seconds")// dropFirst: 删除第一个发布 数组值，因为初始化为空数组，取的是第二个数组，模拟服务数据返回的数组vm.$dataArray.dropFirst().sink { returnedItems inexpectation.fulfill()}.store(in: &cancellables)vm.downloadWithCombine()// Then 断言 = 判定 GreaterThan：大于// 为了安全获取到值，设置等待 5 秒wait(for: [expectation], timeout: 5)XCTAssertGreaterThan(vm.dataArray.count, 0)XCTAssertEqual(vm.dataArray.count, items.count)}
}

3. 模拟请求数据 单元测试

  3.1 创建模拟请求数据类 NewMockDataService.swift

import Foundation
import SwiftUI
import Combine/// 定义协议
protocol NewDataServiceProtocol{func downloadItemsWithEscaping(completion: @escaping (_ items: [String]) -> ())func downloadItemsWithCombine() -> AnyPublisher<[String], Error>
}/// 实现模拟请求数据
class NewMockDataService: NewDataServiceProtocol {let items: [String]init(items: [String]?) {self.items = items ?? ["ONE", "TWO", "THREE"]}/// 模拟网络下载数据 escaping: 转义字符func downloadItemsWithEscaping(completion: @escaping (_ items: [String]) -> ()) {DispatchQueue.main.asyncAfter(deadline: .now() + 2) {completion(self.items)}}/// 下载组合func downloadItemsWithCombine() -> AnyPublisher<[String], Error> {// 数据转换Just(self.items).tryMap({ publishedItems inguard !publishedItems.isEmpty else {throw URLError(.badServerResponse)}return publishedItems}).eraseToAnyPublisher()}
}

  3.2 创建单元测试类 NewMockDataService_Tests.swift

import XCTest
import Combine
/// 导入项目
@testable import SwiftfulThinkingAdvancedLearningfinal class NewMockDataService_Tests: XCTestCase {/// 随时取消控制器var cancellable = Set<AnyCancellable>()override func setUpWithError() throws {// Put setup code here. This method is called before the invocation of each test method in the class.}override func tearDownWithError() throws {// Put teardown code here. This method is called after the invocation of each test method in the class.cancellable.removeAll()}//  单元测试函数名 根据命名规则命名 - 测试_类名_初始化_预期值：正确的设置值func test_NewMockDataService_init_doesSetValuesCorrectly() {// 执行// Given: 给定let items: [String]? = nillet items2: [String]? = []let items3: [String]? = [UUID().uuidString, UUID().uuidString]// When: 时间let dataService = NewMockDataService(items: items)let dataService2 = NewMockDataService(items: items2)let dataService3 = NewMockDataService(items: items3)// Then 然后XCTAssertFalse(dataService.items.isEmpty)XCTAssertTrue(dataService2.items.isEmpty)XCTAssertEqual(dataService3.items.count, items3?.count)}//  单元测试函数名 根据命名规则命名 - 测试_类名_下载转换数据项_预期值：正确的设置值func test_NewMockDataService_downloadItemsWithEscaping_doesReturnValues() {// 执行// Given: 给定let dataService = NewMockDataService(items: nil)// When: 时间var items: [String] = []let expectation = XCTestExpectation()dataService.downloadItemsWithEscaping { returnedItems initems = returnedItemsexpectation.fulfill()}// Then 然后// 等待 5 秒wait(for: [expectation], timeout: 5)// 断言两个数组大小一样XCTAssertEqual(items.count, dataService.items.count)}//  单元测试函数名 根据命名规则命名 - 测试_类名_下载数据项组合_预期值：正确的设置值func test_NewMockDataService_downloadItemsWithCombine_doesReturnValues() {// 执行// Given: 给定let dataService = NewMockDataService(items: nil)// When: 时间var items: [String] = []let expectation = XCTestExpectation()// 下载组合控制dataService.downloadItemsWithCombine().sink { completion inswitch completion{case .finished:expectation.fulfill()case .failure:XCTFail()}} receiveValue: {returnedItems in// fulfill: 完成items = returnedItems}.store(in: &cancellable)// Then 然后// 等待 5 秒wait(for: [expectation], timeout: 5)// 断言两个数组大小一样XCTAssertEqual(items.count, dataService.items.count)}//  单元测试函数名 根据命名规则命名 - 测试_类名_下载数据项组合_预期值：确实失败func test_NewMockDataService_downloadItemsWithCombine_doesFail() {// 执行// Given: 给定let dataService = NewMockDataService(items: [])// When: 时间var items: [String] = []let expectation = XCTestExpectation(description: "Does throw an error")let expectation2 = XCTestExpectation(description: "Does throw URLError.badServerResponse")// 下载组合控制dataService.downloadItemsWithCombine().sink { completion inswitch completion{case .finished:XCTFail()case .failure(let error):expectation.fulfill()//let urlError = error as? URLError// 断言，判定//XCTAssertEqual(urlError, URLError(.badServerResponse))// 错误判断if error as? URLError == URLError(.badServerResponse) {expectation2.fulfill()}}} receiveValue: {returnedItems in// fulfill: 完成items = returnedItems}.store(in: &cancellable)// Then 然后// 等待 5 秒wait(for: [expectation, expectation2], timeout: 5)// 断言两个数组大小一样XCTAssertEqual(items.count, dataService.items.count)}
}

4. 创建单元测试 View，调用测试的 ViewModel UnitTestingBootcampView.swift

import SwiftUI/*1. Unit Test : 单元测试- test the business logic in your app : 测试应用中的业务逻辑2. UI  Test :  界面测试- test the UI of your app : 测试应用中的界面*//// 单元测试
struct UnitTestingBootcampView: View {@StateObject private var vm: UnitTestingBootcampViewModelinit(isPremium: Bool){_vm = StateObject(wrappedValue: UnitTestingBootcampViewModel(isPremium: isPremium))}var body: some View {Text(vm.isPremium.description)}
}struct UnitTestingBootcampView_Previews: PreviewProvider {static var previews: some View {UnitTestingBootcampView(isPremium: true)}
}