Files
carousel/tests/core.test.ts
T

58 lines
1.5 KiB
TypeScript

import { beforeEach, expect, test, vi } from 'vitest';
import { createCarousel } from '../src/index.ts';
// Minimal IO shim — records instances so tests can fire entries manually.
class IOShim {
static last: IOShim | null = null;
cb: IntersectionObserverCallback;
elements: Element[] = [];
constructor(cb: IntersectionObserverCallback) {
this.cb = cb;
IOShim.last = this;
}
observe(el: Element) {
this.elements.push(el);
}
unobserve() {}
disconnect() {}
// helper: emit "slide i is the one intersecting" (ratio 1), others 0
emit(i: number) {
this.cb(
this.elements.map((target, idx) => ({
target,
isIntersecting: idx === i,
intersectionRatio: idx === i ? 1 : 0,
})) as unknown as IntersectionObserverEntry[],
this as unknown as IntersectionObserver,
);
}
}
vi.stubGlobal('IntersectionObserver', IOShim);
function makeTrack(n: number): HTMLElement {
const track = document.createElement('div');
for (let i = 0; i < n; i++) {
const slide = document.createElement('div');
slide.className = 'slide';
track.append(slide);
}
track.scrollTo = vi.fn();
return track;
}
let track: HTMLElement;
beforeEach(() => {
track = makeTrack(3);
});
test('count reflects slide children', () => {
const c = createCarousel(track);
expect(c.count).toBe(3);
});
test('next/prev clamp to range and scroll to target offset', () => {
const c = createCarousel(track);
c.next();
expect(track.scrollTo).toHaveBeenCalled();
});