adding playlist specs

app/coffeescripts/learn/collections.coffee

@@ -0,0 +1,17 @@
+# COLLECTIONS
+
+@app = window.app ? {}
+
+class Albums extends Backbone.Collection
+  model: window.app.Album
+  url: '/api/albums'
+
+class Playlist extends Albums
+  isFirstAlbum: (index) ->
+    index == 0
+  isLastAlbum: (index) ->
+    index == (@models.length - 1)
+
+
+@app.Albums = Albums
+@app.Playlist = Playlist

app/coffeescripts/learn/models.coffee

@@ -3,7 +3,7 @@
 class Album extends Backbone.Model
   isFirstTrack: (index) ->
     index == 0
-  isFirstTrack: (index)->
+  isLastTrack: (index)->
     index >= this.get('tracks').length - 1
   trackUrlAtIndex: (index) ->
     if this.get('tracks').length >= index
@@ -12,4 +12,4 @@ class Album extends Backbone.Model
       null
 
 @app = window.app ? {}
-@app.Album = Album
+@app.Album = Album

spec/coffeescripts/collections_spec.coffee

@@ -0,0 +1,34 @@
+app = window.app ? {}
+
+albumData = [{
+  "title":  "Album A"
+  "artist": "Artist A"
+  "tracks": [{"title": "Track A", "url": "/music/Album A Track A.mp3" },{ "title": "Track B", "url": "/music/Album A Track B.mp3" }]
+  },{
+  "title": "Album B"
+  "artist": "Artist B"
+  "tracks": [{"title": "Track A", "url": "/music/Album B Track A.mp3" },{ "title": "Track B", "url": "/music/Album B Track B.mp3" }]
+}]
+
+describe "Playlist", ->
+  beforeEach ->
+    @playlist = new app.Playlist
+    @playlist.add(albumData[0])
+
+  it "has models", ->
+    expect(@playlist.models.length).toEqual(1)  
+
+  it "identifies first album as first", ->
+    expect(@playlist.isFirstAlbum(0)).toBeTruthy()
+
+  it "rejects non-first album as first", ->
+    expect(@playlist.isFirstAlbum(1)).toBeFalsy()
+
+  it "identifies last album as last", ->
+    @playlist.add(albumData[1])
+    console.log(@playlist)
+    expect(@playlist.isLastAlbum(1)).toBeTruthy()
+
+  it "rejects non-last album as last", ->
+    @playlist.add(albumData[1]) 
+    expect(@playlist.isLastAlbum(0)).toBeFalsy()

spec/coffeescripts/models_spec.coffee

@@ -17,4 +17,23 @@ describe "Album", ->
   it "creates from data", ->
     expect(@album.get('tracks').length).toEqual(2)
 
+  describe "first track", -> 
+    it "returns true for first track", ->
+      expect(@album.isFirstTrack(0)).toBeTruthy()
 
+    it "returns false for other tracks", ->
+      expect(@album.isFirstTrack(12)).toBeFalsy()
+
+  describe "last track", -> 
+    it "returns true for first track", ->
+      expect(@album.isLastTrack(1)).toBeTruthy()
+
+    it "returns false for other tracks", ->
+      expect(@album.isLastTrack(0)).toBeFalsy()
+
+  describe "track url at index", -> 
+    it "returns URL for existing track", ->
+      expect(@album.trackUrlAtIndex(0)).toEqual('/music/Album A Track A.mp3')
+
+    it "returns null for non-existing track", ->
+      expect(@album.trackUrlAtIndex(5)).toBe(null)

spec/javascripts/support/jasmine.yml

@@ -16,7 +16,9 @@ src_files:
     - public/javascripts/vendor/json2.js
     - public/javascripts/vendor/jquery.min.js
     - public/javascripts/vendor/backbone.min.js
-    - public/javascripts/learn/*.js
+    - public/javascripts/learn/models.js
+    - public/javascripts/learn/collections.js
+    - public/javascripts/learn/util.js
     - public/javascripts/*.js
 
 # stylesheets