import { describe, it, expect } from 'vitest'
import { createLimiter } from '../src/main/concurrency'

describe('createLimiter', () => {
  it('동시 실행 수가 limit을 넘지 않는다', async () => {
    const limit = createLimiter(2)
    let active = 0
    let maxActive = 0

    const task = () =>
      limit(async () => {
        active++
        maxActive = Math.max(maxActive, active)
        await new Promise((r) => setTimeout(r, 10))
        active--
      })

    await Promise.all(Array.from({ length: 10 }, task))
    expect(maxActive).toBeLessThanOrEqual(2)
  })

  it('모든 작업의 결과를 반환한다', async () => {
    const limit = createLimiter(3)
    const results = await Promise.all(
      Array.from({ length: 5 }, (_, i) => limit(async () => i * 2))
    )
    expect(results).toEqual([0, 2, 4, 6, 8])
  })
})