tennis started

test.test.ts

// tennis scoring a game
// love, 15, 30, 40  -> game
// unless both 40 its deuce
// player1: adv -> game (if p1 scores)
// adv -> deuce (if p2 scores)

// enter a score

type Command = 'start game'| 'player1' | 'player2'

type State =
  | 'not started'
  | 'love-love'
  | '15-15'
  | '30-15'
  | '30-30'
  | '40-15'

const score = (currentScore: State, command: Command): State => {
  if(command == 'start game' && currentScore == 'not started') return 'love-love'
  if(command === 'player2' && currentScore == '30-15') return '30-30'
  if (command == 'player1' && currentScore == '15-15') {
        return '30-15'
      }
      return '40-15'
    }

describe('tennis scoring will', () => {
   test('game starts at love-love', () => {
    expect(score('not started', 'start game')).toBe('love-love')
   })
  
  test('15-15, play1scores score should be 30-15', () => {
    expect(score('15-15', 'player1')).toBe('30-15')
  })

  test('30-15, play1scores score should be 40-15', () => {
    expect(score('30-15', 'player1')).toBe('40-15')
  })

  test('30-15, play2scores score should be 30-30', () => {
    expect(score('30-15', 'player2')).toBe('30-30')
  })

  test('15-15, play1scores score should be 30-15', () => {
    expect(score('15-15', 'player1')).toBe('30-15')
  })
})