How to use the ng2-toastr.ToastModule.forRoot function in ng2-toastr

beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [SharedModule, ToastModule.forRoot(), RouterTestingModule, HttpClientTestingModule],
      declarations: [UserListComponent]
    }).compileComponents();
  }));

beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [
        ReactiveFormsModule,
        ComponentsModule,
        HttpClientTestingModule,
        ServicesModule,
        ApiModule,
        ToastModule.forRoot()
      ],
      declarations: [ RbdSnapshotFormComponent ],
      providers: [ BsModalRef, BsModalService, AuthStorageService ]
    })
    .compileComponents();
  }));

import {ToastModule} from 'ng2-toastr';
import {ErrorHandleService} from './services/error-handle.service';
import {FormHelperService} from './services/form-helper.service';
/**
 * Created by Ron on 03/10/2016.
 */

@NgModule({
    imports: [
        BrowserModule,
        HttpModule,
        FormsModule,
        ReactiveFormsModule,
        routing,
        Ng2UiAuthModule.forRoot(MyAuthConfig),
        ToastModule.forRoot(),
    ],
    providers: [
        ErrorHandleService,
        FormHelperService,
        CLIENT_ROUTER_PROVIDERS
    ],
    declarations: [
        ClientComponent,
        MainComponent,
        LoginComponent,
        SignupComponent
    ],
    bootstrap: [
        ClientComponent
    ]
})

AdminPageComponent,
    EditUsersFormsComponent,
    AdminComponent,
    UserProfileComponent,
    ChangePasswordComponent
  ],
  imports     : [
    BrowserModule,
    CommonModule,
    FormsModule,
    HttpModule,
    RouterModule,
    ReactiveFormsModule,
    routing,
    BrowserAnimationsModule,
    ToastModule.forRoot(),
    Ng2Bs3ModalModule
  ],
  providers   : [
    AuthGuardService,
    {provide: LocationStrategy, useClass: HashLocationStrategy},
    AuthService,
    ErrorService,
    FormService,
    AdminService,
    AdminGuardService,
    ProfileService,
    {provide: ToastOptions, useClass: CustomOption},
    {
      provide   : AuthHttp,
      useFactory: getAuthHttp,
      deps      : [Http]

beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [
        UiModule,
        TranslateModule.forRoot(),
        RouterTestingModule.withRoutes([
          { path: 'evictions', component: EvictionsComponent},
          { path: 'evictors', component: EvictionsComponent}
        ]),
        RankingModule.forRoot(config),
        ServicesModule.forRoot(),
        ToastModule.forRoot()
      ]
    });
    TestBed.overrideComponent(EvictionsComponent, {
      set: {
        providers: [
          { provide: RankingService, useClass: RankingServiceStub },
          { provide: TranslatePipe, useClass: TranslatePipeMock },
          DecimalPipe
        ]
      }
    })
    .compileComponents();
  }));