text: const expect = require('chai').expect
  const { Puzzle } = require('../../lib/puzzle')
  const { hiddenPairs } = require('../../lib/strategies')
  
  describe('Naked Pairs Strategy', () => {
    it('should find at least one solution', () => {
      const p = Puzzle.fromSymbols([
        [0, 0, 0, 0],
        [0, 0, 0, 0],
        [0, 0, 0, 0],
        [0, 0, 0, 0]
      ])
  
      p.cells[0][0].candidates.set(['1', '2', '3'])
      p.cells[0][1].candidates.set(['1', '2', '4'])
      p.cells[0][2].candidates.set(['4', '5'])
      p.cells[0][3].candidates.set(['6', '7'])
  
      expect(p.applyStrategy(hiddenPairs)).to.equal(true)
      expect(p.cells[0][0].candidates.candidates).to.deep.equal(['1', '2'])
      expect(p.cells[0][1].candidates.candidates).to.deep.equal(['1', '2'])
  
      p.print()
    })
  })
  