ApplicationDecorator generator (#796)

* un-skip test and remove unused class definition

* fix build

* add InstallGenerator

* re-namespace generators

* remove module namespacing

* update README with new generator command

* inherit from Base instead of NamedBase

* add inheritance line to Generators section of README

* call #copy_file instead of #template

* remove skip functionality

* refactor once-used variable

* specify application_decorator.rb file instead of class

* move decorator generator back to rails namespace

* revert README change

* specify decorator class

* re-word template help text

* remove unnecessary describe block

* remove delegate_all from application_decorator template

* edit README

README.md

@@ -139,6 +139,12 @@ end
 
 ### Generators
 
+To create an `ApplicationDecorator` that all generated decorators inherit from, run...
+
+```
+rails generate draper:install
+```
+
 When you have Draper installed and generate a controller...
 
 ```

lib/generators/draper/install_generator.rb

@@ -0,0 +1,14 @@
+module Draper
+  module Generators
+    class InstallGenerator < Rails::Generators::Base
+      source_root File.expand_path('../templates', __FILE__)
+
+      desc 'Creates an ApplicationDecorator, if none exists.'
+
+      def create_application_decorator
+        file = 'application_decorator.rb'
+        copy_file file, "app/decorators/#{file}"
+      end
+    end
+  end
+end

lib/generators/draper/templates/application_decorator.rb

@@ -0,0 +1,8 @@
+class ApplicationDecorator < Draper::Decorator
+  # Define methods for all decorated objects.
+  # Helpers are accessed through `helpers` (aka `h`). For example:
+  #
+  #   def percent_amount
+  #     h.number_to_percentage object.amount, precision: 2
+  #   end
+end

lib/generators/rails/decorator_generator.rb

@@ -1,6 +1,6 @@
 module Rails
   module Generators
-   class DecoratorGenerator < NamedBase
+    class DecoratorGenerator < NamedBase
       source_root File.expand_path("../templates", __FILE__)
       check_class_collision suffix: "Decorator"
 
@@ -24,13 +24,6 @@ module Rails
           end
         end
       end
-
-      # Rails 3.0.X compatibility, stolen from https://github.com/jnunemaker/mongomapper/pull/385/files#L1R32
-      unless methods.include?(:module_namespacing)
-        def module_namespacing
-          yield if block_given?
-        end
-      end
     end
   end
 end

spec/generators/install/install_generator_spec.rb

@@ -0,0 +1,19 @@
+require 'spec_helper'
+require 'dummy/config/environment'
+require 'ammeter/init'
+require 'generators/draper/install_generator'
+
+describe Draper::Generators::InstallGenerator do
+  destination File.expand_path('../tmp', __FILE__)
+
+  before { prepare_destination }
+  after(:all) { FileUtils.rm_rf destination_root }
+
+  describe 'the application decorator' do
+    subject { file('app/decorators/application_decorator.rb') }
+
+    before { run_generator }
+
+    it { is_expected.to contain 'class ApplicationDecorator' }
+  end
+end