How to use the @sweetalert2/ngx-sweetalert2.SweetAlert2Module.forRoot function in @sweetalert2/ngx-sweetalert2

MatAutocompleteModule,
    MatBadgeModule,
    MatBottomSheetModule,
    MatButtonModule,
    MatButtonToggleModule,
    MatCardModule,
    MatCheckboxModule,
    MatChipsModule,
    NgxPaginationModule,
    MatDatepickerModule,
    MatDialogModule,
    MatDividerModule,
    Ng2SearchPipeModule,
    MatExpansionModule,
    MatGridListModule,
    SweetAlert2Module.forRoot(),
    MatIconModule,
    MatInputModule,
    MatListModule,
    MatMenuModule,
    MatNativeDateModule,
    MatPaginatorModule,
    MatProgressBarModule,
    MatProgressSpinnerModule,
    MatRadioModule,
    MatRippleModule,
    MatSelectModule,
    MatSidenavModule,
    MatSliderModule,
    MatSlideToggleModule,
    MatSnackBarModule,
    MatSortModule,

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { SweetAlert2Module } from '@sweetalert2/ngx-sweetalert2';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';

@NgModule({
    declarations: [
        AppComponent
    ],
    imports: [
        BrowserModule,
        SweetAlert2Module.forRoot(),
        AppRoutingModule
    ],
    providers: [],
    bootstrap: [AppComponent]
})
export class AppModule {
}

MatButtonModule,
    MatProgressSpinnerModule,
    MatSelectModule,
    FormsModule,
    FlexLayoutModule,
    ReactiveFormsModule,
    MatTabsModule,
    CovalentDataTableModule,
    CovalentSearchModule,
    CovalentPagingModule,
    MatButtonModule,
    MatDialogModule,
    MatInputModule,
    MatCheckboxModule,
    MatSnackBarModule,
    SweetAlert2Module.forRoot(),
    SvgIconsModule
  ],
  providers: [TdMediaService,
    WorldService,
    AdventureService,
    QuestService,
    TaskService,
    StandardTaskService,
    SpecialTaskService,
    ParticipationService,
    ArtefactService,
    SkillService,
    SonarQubeService,
    UiDesignService,
    AuthenticationService,
    LocalStorageService,

beforeEach(async(() => {
        TestBed.configureTestingModule({
            declarations: [
                AppComponent
            ],
            imports: [
                RouterModule.forRoot([]),
                SweetAlert2Module.forRoot()
            ]
        });

        TestBed.compileComponents();
    }));