How to get NGRX reducer state value inside spec ts file in angular 16

Question

I am not able to get reducer state value inside spec ts. Getting below error.

An error was thrown in afterAll TypeError: Cannot read properties of undefined (reading 'isLoading')

app.component.ts:

let isLoading:Boolean;

public isLoadingValue(){
  this._store$
  .pipe(
  takeUntil(this._destroy$),
  select((store: IStore) => store.dsPowerCreateReducer.isLoading),//Getting error for isLoading
  )
 .subscribe((isLoading: boolean) => {
 this.isLoading = isLoading;
 });
 }

app.component.spec.ts:

it('should set isLoading correctly', () => {
spyOn(store, 'pipe').and.returnValue(of(true));
component.isLoading = true;
component.isLoadingValue();//Getting Error for isLoading
expect(component.isLoading).toBeTrue();
});

i-create.ts

 export interface ICreateReducerState {
    isLoading: boolean;
    meta: any;
  }

reducer.ts:

import { ICreateReducerState } from "./i-create"; 
export class NewCreateApiReducer {
    public static readonly _initialState: ICreateReducerState = {
        isLoading: false,
        meta: null,
    };
}

store.ts:

 readonly dsPowerCreateReducer: ICreateReducerState;