describe('NonEmptyArray operations', () => {
  it('maps over non-empty array', () => {
    const arr: NEA.NonEmptyArray<number> = [1, 2, 3]
    const result = mapNonEmpty(arr)
    expect(result).toEqual([2, 4, 6])
  })

  it('concatenates non-empty arrays', () => {
    const arr1: NEA.NonEmptyArray<number> = [1, 2]
    const arr2: NEA.NonEmptyArray<number> = [3, 4]
    const result = concatNonEmpty(arr1, arr2)
    expect(result).toEqual([1, 2, 3, 4])
  })

  it('concat preserves non-emptiness', () => {
    const arr1 = NEA.of(1)
    const arr2 = NEA.of(2)
    const result = concatNonEmpty(arr1, arr2)
    expect(result.length).toBeGreaterThan(0)
  })
})