如何配置服务以进行角度单元测试

Question

其中一个服务（ProductService）依赖于LoggerService，想要对ProductService执行单元测试。 Spyobj Loggerservice 在测试床的提供者中注册，并且在测试用例中将使用 TestBed.Inject(ProductService) 获取 ProductService。

将测试用例与 angular.io 中可用的示例之一进行比较 -> https://angular.io/guide/testing-services 在示例中，服务和依赖服务都在测试台的提供者中注册。

在使用 TestBed.Inject 获取 ProductService 之前，我们是否需要在测试台的提供程序数组中注册？

            let masterService: MasterService;
            let valueServiceSpy: jasmine.SpyObj<ValueService>;

            beforeEach(() => {
              const spy = jasmine.createSpyObj('ValueService', ['getValue']);

              TestBed.configureTestingModule({
                // Provide both the service-to-test and its (spy) dependency
                providers: [
                  MasterService,
                  { provide: ValueService, useValue: spy }
                ]
              });
              // Inject both the service-to-test and its (spy) dependency
              masterService = TestBed.inject(MasterService);
              valueServiceSpy = TestBed.inject(ValueService) as jasmine.SpyObj<ValueService>;
            });


            export class LogserviceService {

              constructor() { }

              public logMessage(value:string)
              {
                console.log(value);
              }
            }

            export class ProductService {

               products:IProduct[]=[];

              constructor(private logservice:LogserviceService) {
                console.log('getting the service created');
                console.log(logservice);
                console.log(logservice instanceof (LogserviceService));
               }
              getProducts(): IProduct[] {

                this.products =
                [
                  {name:"TV",cost:100,model:"123434",category:"Electronics"},
                 
                ];

                this.logservice.logMessage("I am in the product service");

                return this.products;
              }

              getProduct(category:string):IProduct[]
              {
                this.logservice.logMessage("callling getProduct");

                let products = this.getProducts();
                let prodct= products.filter(x=>x.category ===category);
                return prodct;
              }

            }

            describe('ProductService', () => {
              let service: ProductService;
              let logService: LogserviceService;

              logService = jasmine.createSpyObj(['logMessage']);
              beforeEach(() => {
                TestBed.configureTestingModule({
                  providers: [{ provide: LogserviceService, useValue: logService },
                    
                  ],
                });
              });

             
              it('should get the product list, if valid caterogy is sent', () => {
               
                let service = TestBed.inject(ProductService);  //product service not registered in the providers
                let products = service.getProduct('Electronics');

                expect(products.length).toBeGreaterThan(0);
                expect(logService.logMessage).toHaveBeenCalledWith('callling getProduct');
                expect(products[0].category).toEqual('Electronics');

              });
            });