import { createPromise, isPromise, promisify, sleep, timeout } from './promise'

describe('promises', () => {
  async function demo() {
    return 999
  }

  function demoSync() {
    return 888
  }

  it('should identify promise', async () => {
    expect(isPromise(null)).toBe(false)
    expect(isPromise(new Promise(r => 1))).toBe(true)
    expect(isPromise(demo)).toBe(false)
    expect(isPromise(demo())).toBe(true)
    expect(isPromise(await demo())).toBe(false)
  })

  it('should await', async () => {
    expect(await promisify(demo())).toBe(999)
    expect(await promisify(await demo())).toBe(999)
    expect(await promisify(demoSync())).toBe(888)
  })

  it('should timeout', async () => {
    const r = await timeout(sleep(1000), 500)
    expect(r).toBe('timeoutReached')
    const r2 = await timeout(
      (async () => {
        return 123
      })(),
      500,
    )
    expect(r2).toBe(123)
  })

  it('should create promise', async () => {
    const [promise, resolve] = createPromise()
    setTimeout(() => {
      resolve(5)
    }, 50)
    const result = await promise
    expect(result).toEqual(5)
  })
})