remove newlines from runtime bundle IDs

* create `staged_test.rb` for testing staged Casks
* test an actual staged Cask rather than mocking

lib/cask/staged.rb

@@ -15,6 +15,6 @@ module Cask::Staged
   end
 
   def bundle_identifier
-    plist_exec('Print CFBundleIdentifier')
+    plist_exec('Print CFBundleIdentifier').stdout.chomp
   end
 end

test/cask/dsl/postflight_test.rb

@@ -29,7 +29,7 @@ describe Cask::DSL::Postflight do
       ['/usr/libexec/PlistBuddy', '-c', 'Print CFBundleIdentifier', @dsl.info_plist],
       'com.example.BasicCask'
     )
-    @dsl.bundle_identifier.stdout.must_equal 'com.example.BasicCask'
+    @dsl.bundle_identifier.must_equal 'com.example.BasicCask'
   end
 
   it "can set a key in the Info.plist file" do

test/cask/staged_test.rb

@@ -0,0 +1,19 @@
+require 'test_helper'
+
+# todo: this test should be named after the corresponding class, once
+# that class is abstracted from installer.rb.  It makes little sense
+# to be invoking bundle_identifier off of the postflight instance.
+describe "Operations on staged Casks" do
+  describe "bundle ID DSL" do
+    it "fetches the bundle ID from a staged cask" do
+      transmission_cask  = Cask.load('local-transmission')
+      tr_installer  = Cask::Installer.new(transmission_cask)
+      tr_postflight = Cask::DSL::Postflight.new(transmission_cask)
+
+      shutup do
+        tr_installer.install
+      end
+      tr_postflight.bundle_identifier.must_equal('org.m0k.transmission')
+    end
+  end
+end