`TypeError: Converting circular structure to JSON` error when writing tests for an angular component that utilizes routerLink, Spectator, and Jest

Question

I'm trying to slowly whittle away at errors within a complex module in my application while setting up a new testbed for my application. I'm utilizing the routing factory api from spectator to create my test bed (https://github.com/ngneat/spectator#testing-with-routing)

describe('LoginComponent', () => {
  let spectator: SpectatorRouting<LoginComponent>;
  let defaultComponentSettings = {
    component: LoginComponent,
    componentMocks: [SessionQuery],
    componentProviders: [
      mockProvider(SessionService, {
        credentials: { email: 'name@example.com' }
      })
    ],
    imports: [...imports, HttpClientTestingModule],
    url: [new UrlSegment('/login', {})]
  };

  let createTargetRedirectUrlComponent = createRoutingFactory({
    ...defaultComponentSettings,
    queryParams: {
      redirectUrl: 'http://any/'
    }
  });

  describe('with target redirectUrl', () => {
    beforeEach(() => {
      spectator = createTargetRedirectUrlComponent();
      spectator.component.mfa_token_view$ = of(false);
      spectator.detectChanges();
    });

    it('should have a sign up link', () => {
      console.log('do we have a form yet', spectator.query('form'));
      expect(spectator.query(byText('Sign up'))).toBeTruthy();
    });
  });
});

Now things seem to work fine until until I add an anchor with a [routerLink] directive in my template <a [routerLink]="['/signup']" class="auth-link">Sign up</a>, this for some reason generates the following error:

  ● Test suite failed to run

    TypeError: Converting circular structure to JSON
        --> starting at object with constructor 'Object'
        |     property 'element' -> object with constructor 'Object'
        |     property 'publicProviders' -> object with constructor 'Object'
        |     property 'RouterLink_109' -> object with constructor 'Object'
        --- property 'parent' closes the circle
        at stringify (<anonymous>)

      at messageParent (node_modules/jest-runner/node_modules/jest-worker/build/workers/messageParent.js:34:19)

And I have no idea really how to diagnose this further

Answer 1

Aw, found the answer!

The imports list included a module that itself imported RouterModule, removing this fixed the error.