Use one-liners in specs where possible

spec/controllers/api/application_controller_spec.rb

@@ -3,14 +3,10 @@ require 'spec_helper'
 describe API::ApplicationController do
   include UserControllerHelpers
 
-  before do
-    sign_in
-  end
+  before { sign_in }
 
   context 'CORS: Cross-Origin Ressource Sharing' do
-    before do
-      request.headers['Origin'] = 'http://origin.example/'
-    end
+    before { request.headers['Origin'] = 'http://origin.example/' }
 
     context 'preflight' do
       controller(API::ApplicationController) do

spec/controllers/api/playlists_controller_spec.rb

@@ -3,9 +3,7 @@ require 'spec_helper'
 describe API::PlaylistsController do
   include UserControllerHelpers
 
-  before do
-    sign_in
-  end
+  before { sign_in }
 
   describe 'GET index' do
     render_views

spec/controllers/api/sessions_controller_spec.rb

@@ -12,9 +12,7 @@ describe API::SessionsController do
     end
 
     context 'with valid credentials' do
-      before do
-        do_create
-      end
+      before { do_create }
 
       it 'signs the user in' do
         expect(controller.current_user).to eq user

spec/controllers/api/tracks_controller_spec.rb

@@ -3,9 +3,7 @@ require 'spec_helper'
 describe API::TracksController do
   include UserControllerHelpers
 
-  before do
-    sign_in
-  end
+  before { sign_in }
 
   describe 'GET index' do
     render_views