how can resolve this error ( No provider for InjectionToken angularfire2.app.options!) in angular test about firestore?

in my angular test i have this problem in some componente and in the service where i use firestore. for example this is a error in my itemservice: NullInjectorError: R3InjectorError(DynamicTestModule)[ItemService -> AngularFirestore -> InjectionToken angularfire2.app.options -> InjectionToken angularfire2.app.options]: NullInjectorError: No provider for InjectionToken angularfire2.app.options!

import { Injectable } from '@angular/core';
import {
  AngularFirestore,
  AngularFirestoreCollection,
} from '@angular/fire/firestore';

import { Item } from '../../environments/item';
import { Observable } from 'rxjs';
@Injectable({
  providedIn: 'root',
})
export class ItemService {
  itemsCollection: AngularFirestoreCollection<Item> | undefined;
  items: Observable<Item[]>;
  idField: any;
  itemDoc: any;
  constructor(public afs: AngularFirestore) {
    this.items = this.afs
      .collection<Item>('items')
      .valueChanges({ idField: 'id' });
    this.itemsCollection = this.afs.collection<Item>('items');
  }
}

and here is my app-module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { ReactiveFormsModule } from '@angular/forms';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { environment } from '../environments/environment';
import { AngularFireModule } from '@angular/fire';
import {
  AngularFirestore,
  AngularFirestoreModule,
} from '@angular/fire/firestore';
import { ItemsComponent } from './components/items/items.component';
import { ItemService } from './services/item.service';
import { ItemComponent } from './components/item/item.component';
import { RouterModule } from '@angular/router';
import { NavComponent } from './components/nav/nav.component';
import { CartComponent } from './components/cart/cart.component';
import { CartService } from './services/cart.service';

import { AddItemComponent } from './components/add-item/add-item.component';
import { AngularFireDatabaseModule } from '@angular/fire/database';
@NgModule({
  declarations: [
    AppComponent,
    ItemsComponent,
    ItemComponent,
    NavComponent,
    CartComponent,
    AddItemComponent,
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    AngularFirestoreModule,
    AngularFireDatabaseModule,
    AngularFireModule.initializeApp(environment.firebase, 'project2'),
    RouterModule.forRoot([
      { path: '', component: ItemsComponent },
      { path: 'details/:id', component: ItemComponent },
      { path: 'cart', component: CartComponent },
      { path: 'newitem', component: AddItemComponent },
    ]),
    FormsModule,
    ReactiveFormsModule,
  ],
  providers: [CartService, ItemService],
  bootstrap: [AppComponent],
})
export class AppModule {}