Add basic playlists management

* Index of playlists
* Create a new playlist
* Basic playlist model with mandatory name

spec/controllers/playlists_controller_spec.rb

@@ -0,0 +1,67 @@
+require 'spec_helper'
+
+describe PlaylistsController do
+  def valid_attributes
+    {
+      :name => 'Electro'
+    }
+  end
+
+  describe "GET index" do
+    it 'assigns all playlists as @playlists' do
+      playlist = Playlist.create! valid_attributes
+      get :index
+      assigns[:playlists].should == [playlist]
+    end
+  end
+
+  describe "GET new" do
+    it 'assigns a new playlist as @playlist' do
+      get :new
+      assigns[:playlist].should be_a_new(Playlist)
+    end
+  end
+
+  describe "POST create" do
+    let(:playlist) { mock_model(Playlist).as_null_object }
+
+    before do
+      Playlist.stub(:new).and_return(playlist)
+    end
+
+    it 'creates a new playlist' do
+      Playlist.should_receive(:new).
+        with('name' => 'Electro').
+        and_return(playlist)
+      post :create, :playlist => { 'name' => 'Electro' }
+    end
+
+    it 'saves the playlist' do
+      playlist.should_receive(:save)
+      post :create
+    end
+
+    context 'when the playlist saves successfully' do
+      it 'redirects to the playlists index' do
+        post :create
+        response.should redirect_to(:action => 'index')
+      end
+    end
+
+    context 'when the playlist fails to save' do
+      before do
+        playlist.stub(:save).and_return(false)
+      end
+
+      it 'assigns the playlist as @playlist' do
+        post :create
+        assigns[:playlist].should eq(playlist)
+      end
+
+      it 'renders the new template' do
+        post :create
+        response.should render_template('new')
+      end
+    end
+  end
+end