feat(carousel): update test description and improve item selection logic in carousel component

src/app/shared/components/carousel/carousel.component.spec.ts

@@ -120,10 +120,9 @@ describe('CarouselComponent', () => {
     expect(frame.style.width).toBe('632px');
   });
 
-  it('vuelve al extremo opuesto cuando circular está habilitado', () => {
+  it('mantiene preparadas las páginas adyacentes y rota al terminar la transición', () => {
     fixture.componentInstance.circular.set(true);
     fixture.detectChanges();
-    expect(fixture.componentInstance.carousel().circular()).toBe(true);
 
     const host = fixture.nativeElement.querySelector('app-carousel') as HTMLElement;
     const firstItem = fixture.nativeElement.querySelector('.carousel__item') as HTMLElement;

src/app/shared/components/carousel/carousel.component.ts

@@ -137,7 +137,9 @@ export class CarouselComponent<T> implements AfterViewInit {
       return;
     }
 
-    const item = this.viewport().nativeElement.children.item(index) as HTMLElement | null;
+    const item = this.viewport()
+      .nativeElement.querySelectorAll<HTMLElement>('.carousel__item')
+      .item(index);
 
     item?.scrollIntoView({
       behavior: 'smooth',