How to Mock History.state for writing unit tests in angular

Question

I am writing unit tests for my component but having trouble in creating the instance of the component and showing following error,

TypeError: Cannot read property 'patientId' of null 

I have tried mocking all the providers including router and active router My component.ts is

export class PatientInsurancePlanSearchComponent implements OnInit {

  private patientId: number = -1;
  public selectedOrganizationInsurance: OrganizationInsurance;
  public organizationInsurancePlans$: Observable<OrganizationInsurancePlan[]>;

  constructor(
    private router: Router,
    private activatedRoute: ActivatedRoute,
    private biilingHttpService: BillingHttpService
  ) {
    this.selectedOrganizationInsurance = new OrganizationInsurance();
  }

  ngOnInit() {
    this.patientId = history.state.patientId as number;
    this.selectedOrganizationInsurance = history.state.selectedOrganizationInsurance as OrganizationInsurance;
    this.organizationInsurancePlans$ = this.biilingHttpService.getOrganizationInsurancePlans(this.selectedOrganizationInsurance.id);
  }

spec.ts

class FakeInsurancePlanSearchComponent {
  @Input() public organizationInsurancePlans: OrganizationInsurancePlan[] = [];
  @Input() public selectedOrganizationInsurance: OrganizationInsurance;
  }
  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [ PatientInsurancePlanSearchComponent
      , FakeInsurancePlanSearchComponent ],
      imports: [
        StoreModule.forRoot({}),
        HttpClientModule,
        RouterTestingModule,
      ],
      providers: [
        Store,
        {
          provide: ActivatedRoute, useValue: {
            state: of({ selectedorganizationInsurancePlan: 'AETNA'})
        }
      },
      BillingHttpService
      ]
    })
    .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(PatientInsurancePlanSearchComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should create', () => {
    expect(component).toBeTruthy();
  });

Kindly guide me whats i am missing..

Answer 1

If you want to add patientId to the browsers session history stack, you can simply use:

history.pushState(state, title, url);

In your case it should be something like this:

describe(MyComponent.name, () => {
   ...

   beforeEach(() => {
       window.history.pushState({ patientId: 'somevalue'}, '', '');

       ...
   })


   it('...', () => {

   })
}