describe 'A vending machine', ->

  beforeEach ->
    @m = new VendingMachine

  it 'returns product count', ->
    expect(@m.getCount('coke')).toEqual(5)

  it 'returns iced tea count', ->
    expect(@m.getCount('iced tea')).toEqual(5)

  it 'accepts money', ->
    @m.addMoney(100)
    expect(@m.getBalance()).toEqual 100

    @m.addMoney(-10)
    expect(@m.getBalance()).toEqual 100

  it 'should sell us stuff', ->
    expect(@m.buy('coke')).toBe(null)

    @m.addMoney 2
    expect(@m.buy('coke')).toEqual 'coke'

    expect(@m.buy('iced tea')).toEqual 'iced tea'

    expect(@m.buy('coke')).toBe(null)

  it 'should not sell crack', ->
    @m.addMoney(1000)
    expect(@m.getBalance()).toEqual 1000
    expect(@m.buy('crack')).toBe(null)


  it 'should decrement the product count after buying', ->
    @m.addMoney(5)
    previous_count = @m.getCount('coke')
    @m.buy('coke')
    new_count = previous_count - 1
    expect(@m.getCount('coke')).toBe(new_count)

  it 'should give change', ->
    @m.addMoney(2)
    @m.buy('coke')
    expect(@m.demandChange()).toEqual 1
    expect(@m.getBalance()).toEqual 0

  it 'should just work', ->
    @m.addMoney(10)
    @m.buy('coke')
    @m.buy('iced tea')
    expect(@m.demandChange()).toEqual 8
    expect(@m.getBalance()).toEqual 0
    expect(@m.buy('coke'))