display usage documentation when model is invalid

Author: ryanb

features/nifty_scaffold.feature

@@ -38,3 +38,7 @@ Feature: Nifty Scaffold Generator
     And I run "rails g rspec:install"
     And I replace "mock_with :rspec" with "mock_with :mocha" in file "spec/spec_helper.rb"
     Then I should successfully run "rake spec"
+
+  Scenario: Report error when invalid model name
+    Given a new Rails app
+    Then I should see "Usage:" when running "rails g nifty:scaffold name:string parent_id:integer"

features/step_definitions/common_steps.rb

@@ -42,3 +42,7 @@
 Then /^I should successfully run "([^\"]*)"$/ do |command|
   system("cd #{@current_directory} && #{command}").should be_true
 end
+
+Then /^I should see "([^\"]*)" when running "([^\"]*)"$/ do |expected_response, command|
+  `cd #{@current_directory} && #{command}`.should include(expected_response)
+end

lib/generators/nifty.rb

@@ -8,16 +8,21 @@ def self.source_root
       end
 
       def self.banner
-        "#{$0} nifty:#{generator_name} #{self.arguments.map{ |a| a.usage }.join(' ')} [options]"
+        "rails generate nifty:#{generator_name} #{self.arguments.map{ |a| a.usage }.join(' ')} [options]"
       end
-      
+
       private
-      
+
       def add_gem(name, options = {})
         gemfile_content = File.read(destination_path("Gemfile"))
         File.open(destination_path("Gemfile"), 'a') { |f| f.write("\n") } unless gemfile_content =~ /\n\Z/
         gem name, options unless gemfile_content.include? name
       end
+
+      def print_usage
+        self.class.help(Thor::Base.shell.new)
+        exit
+      end
     end
   end
 end

lib/generators/nifty/scaffold/USAGE

@@ -21,7 +21,7 @@ Usage:
     model's attributes. Timestamps are added by default, so you don't have to
     specify them by hand as 'created_at:datetime updated_at:datetime'.
 
-    For example, `nifty_scaffold post name:string content:text hidden:boolean`
+    For example, `nifty:scaffold post name:string content:text hidden:boolean`
     gives you a model with those three attributes, a controller that handles
     the create/show/update/destroy, forms to create and edit your posts, and
     an index that lists them all, as well as a map.resources :posts

lib/generators/nifty/scaffold/scaffold_generator.rb

@@ -25,6 +25,8 @@ class ScaffoldGenerator < Base
       def initialize(*args, &block)
         super
 
+        print_usage unless model_name =~ /^[a-zA-Z_]$/
+
         @controller_actions = []
         @model_attributes = []
         @skip_model = options.skip_model?