UnhandledPromiseRejectionWarning: TypeError: Conversión de estructura circular a JSON con Jest + Angular

Question

Usando jest-preset-angular para realizar la prueba unitaria, pero recibí una advertencia porque UnhandledPromiseRejectionWarning: TypeError: Converting circular structure to JSONno estaba seguro de qué causaba el error, debido a esto, la aplicación está bloqueada y no está ejecutando la otra prueba unitaria.

PASS  src/app/pages/result/result-filter/result-filter.component.spec.ts (6.251 s)
 PASS  src/app/pages/result/search-navigation/search-navigation.component.spec.ts
 PASS  src/app/pages/result/filter-modal/filter-modal.component.spec.ts (5.699 s)
 PASS  src/app/app.component.spec.ts
 PASS  src/app/pages/test-type/test-type.component.spec.ts (12.857 s)
(node:3280) UnhandledPromiseRejectionWarning: TypeError: Converting circular structure to JSON
    --> starting at object with constructor 'Object'
    |     property 'element' -> object with constructor 'Object'
    |     property 'componentProvider' -> object with constructor 'Object'
    --- property 'parent' closes the circle
    at stringify (<anonymous>)
    at writeChannelMessage (internal/child_process/serialization.js:117:20)
    at process.target._send (internal/child_process.js:808:17)
    at process.target.send (internal/child_process.js:706:19)
    at reportSuccess (/Users/macbook/Projects/Playtime Projects/IDP/Idp.Bx.Ui/idp/node_modules/jest-worker/build/workers/processChild.js:67:11)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:3280) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:3280) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
(node:3281) UnhandledPromiseRejectionWarning: TypeError: Converting circular structure to JSON
    --> starting at object with constructor 'Object'
    |     property 'element' -> object with constructor 'Object'
    |     property 'componentProvider' -> object with constructor 'Object'
    --- property 'parent' closes the circle
    at stringify (<anonymous>)
    at writeChannelMessage (internal/child_process/serialization.js:117:20)
    at process.target._send (internal/child_process.js:808:17)
    at process.target.send (internal/child_process.js:706:19)
    at reportSuccess (/Users/macbook/Projects/Playtime Projects/IDP/Idp.Bx.Ui/idp/node_modules/jest-worker/build/workers/processChild.js:67:11)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:3281) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:3281) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
(node:3279) UnhandledPromiseRejectionWarning: TypeError: Converting circular structure to JSON
    --> starting at object with constructor 'Object'
    |     property 'element' -> object with constructor 'Object'
    |     property 'componentProvider' -> object with constructor 'Object'
    --- property 'parent' closes the circle
    at stringify (<anonymous>)
    at writeChannelMessage (internal/child_process/serialization.js:117:20)
    at process.target._send (internal/child_process.js:808:17)
    at process.target.send (internal/child_process.js:706:19)
    at reportSuccess (/Users/macbook/Projects/Playtime Projects/IDP/Idp.Bx.Ui/idp/node_modules/jest-worker/build/workers/processChild.js:67:11)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:3279) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:3279) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

 RUNS  src/app/pages/location/location.component.spec.ts
 RUNS  src/app/pages/signup/signup.component.spec.ts
 RUNS  src/app/pages/login/login.component.spec.ts

Test Suites: 10 passed, 10 of 20 total
Tests:       16 passed, 16 total
Snapshots:   1 obsolete, 5 passed, 5 total
Time:        2180 s

No estoy seguro de cómo ejecutar el nodo --trace-warnings. Parece que es un problema de serialización, incluso es solo una advertencia, pero no estoy seguro de dónde está el problema. ¿Hay alguna forma mejor de encontrar la excepción?

Answer 1

Haz bromas con --detectOpenHandles. Esto le mostrará lo que realmente está mal con su especificación de prueba. Para mí, faltaban las importaciones de Angular Material y las simulaciones de servicio. Es posible que se le solicite que agregue BrowserAnimationsModule, como Nambi eludió en su respuesta

package.json:

"test": "jest --detectOpenHandles"

Answer 2

El problema fue con la operación asincrónica, así que escribiendo el caso de prueba a continuación, resuélvalo por mí

describe('DateSelectionComponent', () => {
  let component: DateSelectionComponent;
  let fixture: ComponentFixture<DateSelectionComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [DateSelectionComponent, SafePipe],
      imports: [
        SharedModule,
        NgReduxTestingModule,
        RouterTestingModule.withRoutes([])
      ],
      providers: [
        {
          provide: PageAPIActions, useValue: { setPageState() { } }
        }
      ]
    }).compileComponents();
    fixture = TestBed.createComponent(DateSelectionComponent);
    component = fixture.componentInstance;

    // Don't use Object.defineProperty when assigning value to class properties
    component.page$ = of('value');
    component.page = { destination: 'value' };
    component.startDate = new NgbDate(2019, 2, 27);
    component.minDate = new NgbDate(2019, 2, 27);
    fixture.detectChanges();
  }));

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

  it('Should Match Snapshot', () => {
     expect(fixture.debugElement.nativeElement).toMatchSnapshot()
  });
});

Answer 3

En mi situación, el error críptico se desencadenó al no importar HttpClientModuleen el archivo de prueba. Más detalles aquí .

Answer 4

Añadiendo mi respuesta para ayudar a alguien si se pierde. En mi caso me he perdido de importar

import { BrowserAnimationsModule } from '@angular/platform-browser/animations';

Capaz de encontrar el problema solo cuando se ejecuta uno de los casos de prueba de forma aislada.