测试平台：为什么注入默认类而不是我的间谍

Question

我有用于测试的设置代码

beforeEach(() => {
        loggerServiceSpy = jasmine.createSpyObj('LoggerService', ['log', 'naam']);
        TestBed.configureTestingModule({
            declarations: [UserslistComponent, BizPipe],
            providers: [
                { provide: UserdataService, useClass: MockUserdataService },
                { provide: LoggerService, useValue: loggerServiceSpy }
            ]
        }).compileComponents();
        fixture = TestBed.createComponent(UserslistComponent); 
        component = fixture.componentInstance;
        fixture.detectChanges();
    });

我要执行的操作是注入MockUserdataService（确实如此）和创建的loggerServiceSpy的实例。

现在在UserslistComponent中，注入的LoggerService类型是“真实” LoggerService，而不是我的间谍。

通过控制台记录LoggerService的名称已经看到了这一点（我为loggerservice提供了name属性）。

这是UserslistComponent的构造函数：  constructor(private userDataService: UserdataService, private logger: LoggerService) {

Answer 1

如果组件中提供了服务，请尝试覆盖该组件：

beforeEach(() => {
        loggerServiceSpy = jasmine.createSpyObj('LoggerService', ['log', 'naam']);
        TestBed.configureTestingModule({
            declarations: [UserslistComponent, BizPipe],

        }).overrideComponent(UserslistComponent, {
            set: {
                providers: [
                { provide: UserdataService, useClass: MockUserdataService },
                { provide: LoggerService, useValue: loggerServiceSpy }
            ],
            }
        }).compileComponents();
        fixture = TestBed.createComponent(UserslistComponent); 
        component = fixture.componentInstance;
        fixture.detectChanges();
    });