More code refactoring.

railties/lib/generators/base.rb

@@ -2,6 +2,11 @@
 
 module Rails
   module Generators
+    DEFAULTS = {
+      :test_framework => 'test_unit',
+      :template_engine => 'erb'
+    }
+
     class Error < Thor::Error
     end
 
@@ -113,39 +118,29 @@ def self.add_shebang_option!
           end
         end
 
-        # Small macro to add test_framework option and invoke it.
+        # Invoke a generator based on the given name. If a class option does not
+        # exist for the current name, it's created.
         #
-        def self.add_and_invoke_test_framework_option!
-          class_option :test_framework, :type => :string, :aliases => "-t", :default => "test_unit",
-                                        :desc => "Test framework to be invoked by this generator", :banner => "NAME"
-
-          define_method :invoke_test_framework do
-            return unless options[:test_framework]
-            name = "#{options[:test_framework]}:generators:#{self.class.generator_name}"
-
-            begin
-              invoke name
-            rescue Thor::UndefinedTaskError
-              say "Could not find and invoke '#{name}'."
+        def self.invoke_for(*names)
+          names.each do |name|
+            unless class_options[name]
+              aliases = "-" + name.to_s.gsub(/_framework$/, '').split('_').last[0,1]
+              class_option name, :type => :string, :default => DEFAULTS[name], :banner => "NAME", :aliases => aliases,
+                                 :desc => "#{name.to_s.humanize} to be used"
             end
-          end
-        end
 
-        # Small macro to add template engine option and invoke it.
-        #
-        def self.add_and_invoke_template_engine_option!
-          class_option :template_engine, :type => :string, :aliases => "-e", :default => "erb",
-                                         :desc => "Template engine to be invoked by this generator", :banner => "NAME"
-
-          define_method :invoke_template_engine do
-            return unless options[:template_engine]
-            name = "#{options[:template_engine]}:generators:#{self.class.generator_name}"
-
-            begin
-              invoke name
-            rescue Thor::UndefinedTaskError
-              say "Could not find and invoke '#{name}'."
-            end
+            class_eval <<-METHOD, __FILE__, __LINE__
+              def invoke_#{name}
+                return unless options[#{name.inspect}]
+                task = "\#{options[#{name.inspect}]}:generators:\#{self.class.generator_name}"
+
+                begin
+                  invoke task
+                rescue Thor::UndefinedTaskError
+                  say "Could not find and invoke '\#{task}'."
+                end
+              end
+            METHOD
           end
         end
 

railties/lib/generators/erb/mailer/templates/view.erb

 <%= class_name %>#<%= @action %>
 
-Find me in <%= @path %>
+Find me in app/views/<%= @path %>

railties/lib/generators/rails/mailer/mailer_generator.rb

@@ -11,8 +11,7 @@ def create_mailer_file
         template "mailer.rb", File.join('app/models', class_path, "#{file_name}.rb")
       end
 
-      add_and_invoke_template_engine_option!
-      add_and_invoke_test_framework_option!
+      invoke_for :template_engine, :test_framework
     end
   end
 end

railties/lib/generators/rails/observer/observer_generator.rb

@@ -9,7 +9,7 @@ def create_observer_file
         template 'observer.rb', File.join('app/models', class_path, "#{file_name}_observer.rb")
       end
 
-      add_and_invoke_test_framework_option!
+      invoke_for :test_framework
     end
   end
 end

railties/lib/generators/rails/plugin/plugin_generator.rb

@@ -27,7 +27,7 @@ def create_lib_files
         directory 'lib'
       end
 
-      add_and_invoke_test_framework_option!
+      invoke_for :test_framework
 
       def create_tasks_files
         return unless options[:with_tasks]

railties/lib/generators/test_unit/mailer/templates/fixture

 <%= class_name %>#<%= @action %>
 
-Find me in <%= @path %>
+Find me in app/views/<%= @path %>

railties/test/generators/app_generator_test.rb

@@ -4,6 +4,16 @@
 
 class AppGeneratorTest < GeneratorsTestCase
 
+  def setup
+    super
+    Rails::Generators::AppGenerator.instance_variable_set('@desc', nil)
+  end
+
+  def teardown
+    super
+    Rails::Generators::AppGenerator.instance_variable_set('@desc', nil)
+  end
+
   def test_application_skeleton_is_created
     run_generator
 
@@ -120,6 +130,20 @@ def test_template_is_executed_when_supplied
     assert_match /It works!/, silence(:stdout){ generator.invoke(:all) }
   end
 
+  def test_usage_read_from_file
+    File.expects(:read).returns("USAGE FROM FILE")
+    assert_equal "USAGE FROM FILE", Rails::Generators::AppGenerator.desc
+  end
+
+  def test_default_usage
+    File.expects(:exist?).returns(false)
+    assert_match /Create rails files for app generator/, Rails::Generators::AppGenerator.desc
+  end
+
+  def test_default_namespace
+    assert_match "rails:generators:app", Rails::Generators::AppGenerator.namespace
+  end
+
   protected
 
     def run_generator(args=[])