在单个测试规范中模拟服务并为所有测试规范全局调用它 Angular 单元测试用例

Question

我已经包含了用于登录功能的 cookieservice，但是在执行单元测试用例时，它显示错误消息No provider for cookieservice for each test specs。 是否有一个选项可以全局模拟 cookieservice，以便它在每个测试规范中调用。 请帮帮我

import { CookieService } from '@alfresco/adf-core';

mockService( CookieService, {
            getItem: () => '',
            setItem: () => {},           
        })

Answer 1

执行的单元测试规范独立于其他规范。 因此，我们需要为所有规范单独注入所有依赖项。 同样，执行的每个单元测试都应该是独立的，应该独立运行。它们不应该影响或应该受其他测试用例的影响。 现在来回答您的问题，如何创建可以为我们在测试台中初始化的每个模块注入的全局模拟，这不是一个好主意，因为它可能不起作用，因为您测试的每个服务可能没有相同数量的依赖项. 相反，我所做的或推荐的如下：

1. 创建一个通过文件导出的模拟对象（您也可以创建一个类）：

    // mocks.ts This can reside at some shared location
    export const CookieServiceMock = {
        setCookie(): void => undefined
    }

2. 用新的模拟注入 TestBed

import { CookieServiceMock } from 'mocks.ts' 
describe('ServiceToTest', () => {
  let serviceToTest: ServiceToTest; // Replace with your service
  beforeEach(() => {
    TestBed.configureTestingModule({
      providers: [
         ServiceToTest
         // Below line will replace your service with mock and
         // needs to be done at all places where cookieService is dependency.
         
         {provide: CookieService, useValue:  CookieServiceMock } 
         //useClass if CookieService mock is a class
         //This way you don't need inject the dependencies explicitly for injected 
         //services.
      ],
      imports: []
    });
     // Get the instance of service to test
     serviceToTest = TestBed.get(ServiceToTest);  
     
     // This will now return the instance of mock i.e. CookieServiceMock object
     cookieService = TestBed.get(CookieService);  
 });

 it('Service to test',()=>{
   // Now you can access all the methods to test within your target service 
   // and also your methods that you want to Spy from your mock.
 })
});

另一种方法是，如果您想为所有测试模块保留一些通用配置，则是：

TestBed.configureTestingModule(
// Extract out this Object. 
// But this might not work in most cases since every service or 
// component to test have a different dependencies.
{ 
      providers: [],
      imports: []
    });