Pruebas a los parámetros

Vamos a hacer las pruebas que estan siendo enrutados y reciben ciertos parametros,

product-detail.component.spec.ts

import { ComponentFixture, TestBed } from '@angular/core/testing';
import { ActivatedRoute } from '@angular/router';
import { Location } from '@angular/common';
import { ActivatedRouteStub, mockObservable } from './../../../../testing';
import { ProductsService } from '../../../services/product.service';
import { generateOneProduct } from '../../../models/product.mock';
import { ProductDetailComponent } from './product-detail.component';

describe('ProductDetailComponent', () => {
  let component: ProductDetailComponent;
  let fixture: ComponentFixture<ProductDetailComponent>;
  let route: ActivatedRouteStub;
  let productsService: jasmine.SpyObj<ProductsService>;
  let location: jasmine.SpyObj<Location>;

  beforeEach(async () => {
    const routeStub = new ActivatedRouteStub();
    const productServiceSpy = jasmine.createSpyObj('ProductsService', ['getOne']);
    const locationSpy = jasmine.createSpyObj('Location', ['back']);

    await TestBed.configureTestingModule({
      declarations: [ ProductDetailComponent ],
      providers: [
        { provide: ActivatedRoute, useValue: routeStub },
        { provide: ProductsService, useValue: productServiceSpy },
        { provide: Location, useValue: locationSpy },
      ],
    })
    .compileComponents();
  });

  beforeEach(() => {
    fixture = TestBed.createComponent(ProductDetailComponent);
    component = fixture.componentInstance;
    route = TestBed.inject(ActivatedRoute) as unknown as ActivatedRouteStub;
    productsService = TestBed.inject(ProductsService) as unknown as jasmine.SpyObj<ProductsService>;
    location = TestBed.inject(Location) as unknown as jasmine.SpyObj<Location>;

    const productId = '1';
    route.setParamMap({id: productId});
    const productMock = {
      ...generateOneProduct(),
      id: productId,
    }
    productsService.getOne.and.returnValue(mockObservable(productMock));
    fixture.detectChanges(); // ngOnInit
  });

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

src/testing/activated-route-stub.ts

import { convertToParamMap, ParamMap, Params } from '@angular/router';
import { ReplaySubject } from 'rxjs';

/**
 * An ActivateRoute test double with a `paramMap` observable.
 * Use the `setParamMap()` method to add the next `paramMap` value.
 */
export class ActivatedRouteStub {
  // Use a ReplaySubject to share previous values with subscribers
  // and pump new values into the `paramMap` observable
  private subject = new ReplaySubject<ParamMap>();

  constructor(initialParams?: Params) {
    this.setParamMap(initialParams);
  }

  /** The mock paramMap observable */
  readonly paramMap = this.subject.asObservable();

  /** Set the paramMap observable's next value */
  setParamMap(params: Params = {}) {
    this.subject.next(convertToParamMap(params));
  }
}