fix for rails app generator when using --pretend option

[#5245 state:committed]
Signed-off-by: NSantiago Pastorino <santiago@wyeworks.com>

railties/lib/rails/generators/rails/app/app_generator.rb

@@ -216,7 +216,7 @@ def create_root
 
         empty_directory '.'
         set_default_accessors!
-        FileUtils.cd(destination_root)
+        FileUtils.cd(destination_root) unless options[:pretend]
       end
 
       def create_root_files

railties/test/generators/app_generator_test.rb

@@ -58,6 +58,12 @@ def test_application_skeleton_is_created
     DEFAULT_APP_FILES.each{ |path| assert_file path }
   end
 
+  def test_application_generate_pretend
+    run_generator ["testapp", "--pretend"]
+
+    DEFAULT_APP_FILES.each{ |path| assert_no_file path }
+  end
+
   def test_application_controller_and_layout_files
     run_generator
     assert_file "app/views/layouts/application.html.erb", /stylesheet_link_tag :all/