Angular 有没有办法用玩笑来测试角度路由器？

我试图测试当用户导航到页面时，侧边栏中的元素是否正确折叠。在我的玩笑测试中，我很难模仿角度路由器

我正在尝试测试的代码：

this.router.events.pipe(
            filter(event => event instanceof NavigationEnd)
        ).subscribe((event: NavigationEnd) => {
            this.current = event.url;
            if (this.current.includes('page1')) {
                this._expandMenu(this.page1Toggle);

                if (this.current.includes('page2')) {
                    this._expandMenu(this.page2Toggle);
                }
            }
            this._closeMenu();
        });

正在尝试模拟路由器：

let eventSubject: Subject<Event> = new Subject<Event>();

export class MockRouter {
    events: Observable<Event> = eventSubject;
}

我已经尝试过像这样提供路由器

{provide:Router，useClass:MockRouter}

但在尝试实例化设备时，会不断出现错误：

let fixture: ComponentFixture<SideBarComponent>;
let comp: SideBarComponent;
beforeEach(() => {
        TestBed.configureTestingModule({
            declarations: [
                SideBarComponent,
            ],
            imports: [
                RouterTestingModule
            ],
            providers: [
                { provide: Router, useClass: MockRouter}
            ]
        }).compileComponents();
fixture = TestBed.createComponent(SideBarComponent); --Cannot read property 'root' of undefined
comp = fixture.componentInstance;

let夹具：组件夹具；
let comp:SideBarComponent；
在每个之前（（）=>{
TestBed.configureTestingModule({
声明：[
侧边栏组件，
],
进口：[
路由测试模块
],
供应商：[
{提供：路由器，useClass:MockRouter}
]
}).compileComponents（）；
fixture=TestBed.createComponent（SideBarComponent）；--无法读取未定义的
comp=夹具。组件状态；

找到了一种更好的方法来处理Angular的显示/折叠功能

值得注意的是，我使用Angular 8和Jest 24.8来实现这一点

let fixture: ComponentFixture<SideBarComponent>;
let comp: SideBarComponent;
beforeEach(() => {
        TestBed.configureTestingModule({
            declarations: [
                SideBarComponent,
            ],
            imports: [
                RouterTestingModule
            ],
            providers: [
                { provide: Router, useClass: MockRouter}
            ]
        }).compileComponents();
fixture = TestBed.createComponent(SideBarComponent); --Cannot read property 'root' of undefined
comp = fixture.componentInstance;