describe('These map', () => {
  it('maps right value', () => {
    const result = doubleValue(Th.right(21))
    expect(result).toEqual(Th.right(42))
  })

  it('maps both value', () => {
    const result = doubleValue(Th.both('warning', 21))
    expect(result).toEqual(Th.both('warning', 42))
  })

  it('leaves left unchanged', () => {
    const result = doubleValue(Th.left('error'))
    expect(result).toEqual(Th.left('error'))
  })

  it('transforms both sides', () => {
    const result = transformBoth(Th.both('warning', 42))
    const expected = Th.both('WARNING: warning', 'Value: 42')
    expect(result).toEqual(expected)
  })
})