describe('TaskEither parallel execution', () => {
  it('fetches all in parallel', async () => {
    const start = Date.now()
    const result = await fetchAllParallel([1, 2, 3])()
    const duration = Date.now() - start

    expect(result._tag).toBe('Right')
    if (result._tag === 'Right') {
      expect(result.right).toEqual([10, 20, 30])
    }
    // Should be faster than sequential (< 25ms vs 30ms)
    expect(duration).toBeLessThan(25)
  })

  it('combines parallel results', async () => {
    const task1 = TE.right(10)
    const task2 = TE.right(20)
    const task3 = TE.right(30)

    const result = await combineResults(task1, task2, task3)()
    expect(result._tag).toBe('Right')
    if (result._tag === 'Right') {
      expect(result.right).toBe(60)
    }
  })
})