text: import fold from './fold'
  
  describe('fold', () => {
    it('handles an array', () => {
      function f (b, a) { return [a].concat(b) }
      expect(fold(f)([])([1, 2, 3])).toEqual([3, 2, 1])
    })
  
    it('handles a string', () => {
      function f (b, a) { return a + b }
      expect(fold(f)('')('foo')).toBe('oof')
    })
  })
  