text: import 'chai/register-should'
  import convert_prop from '../src/properties'
  import seq from '../src/sequence'
  
  describe('properties.js', () => {
      it('can do simple object property mapping', () => {
          const propCon = seq(
              convert_prop('old', 'new'),
              convert_prop('black', 'white'),
              convert_prop('ying', 'yang'),
          )
  
          // forwards
          propCon({
              old: 9,
              black: true,
              ying: 'Hi ying!',
          }).should.deep.equal({
              new: 9,
              white: true,
              yang: 'Hi ying!',
          })
  
          // reverse
          propCon
              .inv({
                  new: 'baby',
                  white: 'elephant',
                  yang: 'Hello yang!',
              })
              .should.deep.equal({
                  old: 'baby',
                  black: 'elephant',
                  ying: 'Hello yang!',
              })
      })
  })
  