49 lines
1.7 KiB
TypeScript
49 lines
1.7 KiB
TypeScript
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import { describe, expect, it } from 'vitest';
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import { nextIndex, swipeStep } from './carousel';
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// 广告轮播纯逻辑（Task 10 Step 1）：推进/环形回绕/单条静止 + 滑动手势判定
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//（阈值 40px、水平分量须严格大于垂直分量）。
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describe('nextIndex', () => {
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it('advances forward and wraps from the tail to the head (ring)', () => {
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expect(nextIndex(3, 0)).toBe(1);
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expect(nextIndex(3, 1)).toBe(2);
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expect(nextIndex(3, 2)).toBe(0); // 末→首
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});
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it('keeps a single item pinned at 0 (never switches)', () => {
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expect(nextIndex(1, 0)).toBe(0);
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expect(nextIndex(1, 0, -1)).toBe(0);
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expect(nextIndex(0, 0)).toBe(0); // 空表防御：同 0
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});
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it('steps backwards wrapping from the head to the tail', () => {
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expect(nextIndex(3, 0, -1)).toBe(2);
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expect(nextIndex(3, 2, -1)).toBe(1);
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expect(nextIndex(5, 4, -1)).toBe(3);
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});
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});
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describe('swipeStep', () => {
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it('maps an unambiguous horizontal swipe to its direction', () => {
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expect(swipeStep(-80, 5)).toBe(1); // 左滑 → 下一张
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expect(swipeStep(80, -5)).toBe(-1); // 右滑 → 上一张
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});
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it('ignores movement under the 40px threshold', () => {
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expect(swipeStep(-39, 0)).toBe(0);
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expect(swipeStep(39, 2)).toBe(0);
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});
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it('accepts exactly 40px (>= threshold)', () => {
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expect(swipeStep(-40, 0)).toBe(1);
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expect(swipeStep(40, 0)).toBe(-1);
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});
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it('ignores diagonal or vertically dominant movement', () => {
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expect(swipeStep(60, 70)).toBe(0); // 垂直分量更大（斜向）
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expect(swipeStep(50, 50)).toBe(0); // 等分量：水平须严格大于垂直
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expect(swipeStep(-100, 100)).toBe(0);
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});
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});
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