Cannot find module 'swiper_angular' on unit test (jest) after upgrading Swiper 6 to 7

Question

I'm running into a problem on my unit tests after upgrading Swiper 6 to 7. I'm using Angular 12 and Swiper 7.3.1. Before upgrading it the unit tests were working fine (Swiper version 6.5.9).

I'm using the SwiperModule in my tests like this:

import { CUSTOM_ELEMENTS_SCHEMA } from '@angular/core';
import { ComponentFixture, TestBed, waitForAsync } from '@angular/core/testing';
import { of } from 'rxjs';
import { SwiperComponent, SwiperModule } from 'swiper/angular';

import { TeaserWrapperContainerComponent } from './teaser-wrapper-container.component';
import { InterfaceState } from '@migrosonline/shared-deps-all/core/interface/interface.store';


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

const mockedSwiperComponent = {
        swiperRef: {
            slideNext: jest.fn(),
            slidePrev: jest.fn(),
            destroy: jest.fn(),
            update: jest.fn()
        }
    } as unknown as SwiperComponent;

beforeEach(
        waitForAsync(() => {
            mockedInterfaceService.prototype.select = jest.fn();

            TestBed.configureTestingModule({
                declarations: [TeaserWrapperContainerComponent],
                imports: [SwiperModule],
                providers: [{ provide: InterfaceService, useClass: mockedInterfaceService }],
                schemas: [CUSTOM_ELEMENTS_SCHEMA]
            }).compileComponents();
        })
    );

    beforeEach(() => {
        fixture = TestBed.createComponent(TeaserWrapperContainerComponent);
        component = fixture.componentInstance;
        component.teaserGroupSliderRef = mockedSwiperComponent;
    });

    it('should create', () => {
        fixture.detectChanges();

        expect(component).toBeTruthy();
    });

});

and the error I get is this:

Cannot find module 'swiper_angular' from 'src/lib/shared/teaser/teaser-wrapper-container/teaser-wrapper-container.component.spec.ts'

      3 | import { of } from 'rxjs';
    > 4 | import { SwiperComponent, SwiperModule } from 'swiper/angular';

I would appreciate any ideas/comments/suggestions.

Answer 1

If you have trouble to import a module, just mock it in this way at the top of your test:

jest.mock('swiper/angular', () => ({
    SwiperModule: jest.fn(),
}));

https://jestjs.io/docs/mock-functions#mocking-modules

If you need to declare the SwiperComponent, just mock it at the top of your test:

@Component({
    selector: 'swiper',
    template: '',
})
export class SwiperMockComponent {
    @Input() pagination = false; // if pagination is needed
}

And declare it in TestBed or MockBuilder:

TestBed.configureTestingModule({
    declarations: [SomeComponent, SwiperMockComponent],
    ...
});