how to write unit test for functionMap and ComponentMap created using new MAp() in angular

Question

I want to write unit test but not getting how i can wrte unit test for the following this is my service class

export class TourStoreServiceService {
  private readonly commandMap = new Map<string, BaseCommand>();
  private readonly functionMap = new Map();
  private readonly componentMap = new Map();
  private sessionId: string;
 
  private sessionGenerator: () => string = () => uuidv4();

  constructor(@Inject(LOCAL_STORAGE) private readonly storage: StorageService) {
   
  }
}

I want to test the following functions

 public registerFnRef(key, fn: () => void): void {
    this.functionMap.set(key, fn);
  }

  public registerComponent(key, component: Type<unknown>) {
    this.componentMap.set(key, component);
  }

  public getFnByKey(key): Function {
    return this.functionMap.get(key);
  }

  public getComponentByKey(key): Type<unknown> {
    return this.componentMap.get(key);
  }

  public generateSessionId(): void {
    this.sessionId = this.sessionGenerator();
    this.storage.set('TOUR_SESSION_ID', this.sessionId);
  }