Как сделать тестирование перехватчика

Question

Я пытаюсь выполнить модульное тестирование перехватчика, используя приведенный ниже код, но я получаю исключение, помогите мне, пожалуйста, написать мой код в stackbliz

https://stackblitz.com/edit/angular-unit-testing-example-xnm226

перехватчик

import { Injectable } from '@angular/core';
import { HttpRequest, HttpHandler, HttpEvent, HttpInterceptor } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { catchError } from 'rxjs/operators';

@Injectable()
export class ErrorInterceptor implements HttpInterceptor {

  constructor() { }

  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    return next.handle(request).pipe(catchError(err => {
      if (err.status === 401) {
      }
      const error = err.error.message || err.statusText;
      return throwError(error);
    }))
  }
}

тест

import { TestBed, inject, async } from "@angular/core/testing";
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';
import { HTTP_INTERCEPTORS, HttpClient, HttpHeaders, HttpRequest, HttpResponse, HttpClientModule, HttpErrorResponse, HttpHandler } from '@angular/common/http';
import { AutherizationInterceptor, InterceptorSkipHeader } from './authInterceptors';
import { ErrorInterceptor } from './errorInterceptors';
import { environment } from 'src/environments/environment';

describe('ErrorInterceptor', () => {
    let http: HttpTestingController;
    let httpClient: HttpClient;
    beforeEach(() => {
        TestBed.configureTestingModule({
            imports: [HttpClientModule, HttpClientTestingModule],
            providers: [{
                provide: HTTP_INTERCEPTORS,
                useClass: ErrorInterceptor,
                multi: true
            }]
        })
        http = TestBed.get(HttpTestingController);
        httpClient = TestBed.get(HttpClient);
    });

    it('Error interceptor test', () => {
        httpClient.get(environment.baseUrl + 'api/user/login').subscribe(
            response => {
                expect(response).toBeTruthy();
            }
        );
        http.expectOne(environment.baseUrl + 'api/user/login').error(new ErrorEvent('Unauthorized error'), {
            status: 401
        });
        http.verify();
    });
});