NullInjectorError: StaticInjectorError(DynamicTestModule)[ToastrService -> InjectionToken ToastConfig]: in tslint angular 8

When i run the unit testing in angular 8 project, i found an error in ngx-toastr

NullInjectorError: StaticInjectorError(DynamicTestModule)[ToastrService -> InjectionToken ToastConfig]:

And i imported the requierd modules in the spec.ts file, And also i declared forRoot() in app.module.ts

  beforeEach(async(() => {
TestBed.configureTestingModule({
  imports: [MatTabsModule,
    ReactiveFormsModule,
    MatTooltipModule,
    HttpClientTestingModule,
    RouterTestingModule,
    ToastrModule
  ],
  declarations: [CommunicationComponent],
  providers: [
    ToastrService,
  ]
})
  .compileComponents();

}));

import { ToastrModule } from 'ngx-toastr';

beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [ToastrModule.forRoot()],

    })
      .compileComponents();
  }));

Add ToastrModule.forRoot() in imports as shown above and your error might be resolved