Angular 单元测试 case 模拟store 中的行为主体

我已经创建了一个存储，以在行为主体中加载地址详细信息

@Injectable({
    providedIn: 'root'
})
export class AddressStore {
    private subjectAddress = new BehaviorSubject<Address[]>([]);
    address$: Observable<Address[]> = this.subjectAddress.asObservable();

    constructor(private addressService: AddressService){
        this.loadAddress();
    }

    private loadAddress(){
        this.addressService.getAddressByType('HOME')
            .subscribe((state => this.subjectAddress.next(state)));
    }
}

我需要模拟单元测试用例中的地址服务返回的数据，但它返回undefined错误:

describe('Address Data Store', () => {
    let addressServiceSpy = jasmine.createSpyObj('AddressService', [
        'getAddressByType',
    ]);
    let addressService: any;
    let addressStore: AddressStore;

    let mockAddress = [
        {
          type: "HOME",
          houseNumber: "101",
          address: "xyz"
        }
    ];

    beforeEach(() => { 
        TestBed.configureTestingModule({
            imports: [
              RouterTestingModule,
              HttpClientTestingModule
            ],
            providers: [
              {
                provide: AddressService,
                useValue: addressServiceSpy
              },
              AddressStore
            ],
        });
        addressService = TestBed.inject(AddressService);
        addressStore = TestBed.inject(AddressStore);
    });

    it('should be created', fakeAsync(() => {
        addressService.getAddressByType.and.returnValue(of(mockAddress));
        expect(addressStore).toBeTruthy();
        flush();
    }));
})

如何在为存储编写单元测试用例的同时模拟服务订阅数据.