Jasmine example converted to CoffeeScript

Player.coffee

class Player	
	play: (song) ->
		@currentlyPlayingSong = song
		@isPlaying = true

	pause: ->
		@isPlaying = false
	
	resume: ->
		throw new Error "song is already playing" if this.isPlaying
		@isPlaying = true

	makeFavorite: ->
  		@currentlyPlayingSong.persistFavoriteStatus true

PlayerSpec.coffee

describe "Player", ->
	player = null
	song = null
	
	beforeEach ->
		player = new Player()
		song = new Song()

	it "should be able to play a Song", ->
		player.play song
		expect(player.currentlyPlayingSong).toEqual song

		# demonstrates use of custom matcher
		expect(player).toBePlaying song

	describe "when song has been paused", ->
		beforeEach ->
			player.play song
			player.pause()

		it "should indicate that the song is currently paused", ->
			expect(player.isPlaying).toBeFalsy()

			# demonstrates use of 'not' with a custom matcher
			expect(player).not.toBePlaying song

		it "should be possible to resume", ->
			player.resume()
			expect(player.isPlaying).toBeTruthy()
			expect(player.currentlyPlayingSong).toEqual song

	# demonstrates use of spies to intercept and test method calls
	it "tells the current song if the user has made it a favorite", ->
		spyOn song, 'persistFavoriteStatus'

		player.play song
		player.makeFavorite()

		expect(song.persistFavoriteStatus).toHaveBeenCalledWith true

	# demonstrates use of expected exceptions
	describe "#resume", ->
		it "should throw an exception if song is already playing", ->
			player.play song
			expect(-> player.resume()).toThrow "song is already playing"

Song.coffee

class Song
	persistFavoriteStatus: ->
  		# something complicated
  		throw new Error "not yet implemented"

SpecHelper.coffee

beforeEach ->
	@addMatchers {
    		toBePlaying: (expectedSong) ->
      			player = @actual
      			player.currentlyPlayingSong == expectedSong and player.isPlaying
  			}