include tests with cancan:ability generator - closes #350

lib/generators/cancan/ability/USAGE

@@ -1,4 +1,5 @@
 Description:
   The cancan:ability generator creates an Ability class in the models
   directory. You can move this file anywhere you want as long as it
-  is in the load path.
+  is in the load path. A test/spec file is also generated depending
+  on if a spec directory exists.

lib/generators/cancan/ability/ability_generator.rb

@@ -1,10 +1,15 @@
 module Cancan
   module Generators
     class AbilityGenerator < Rails::Generators::Base
-      source_root File.expand_path('../templates', __FILE__)
+      source_root File.expand_path("../templates", __FILE__)
 
       def generate_ability
         copy_file "ability.rb", "app/models/ability.rb"
+        if File.exist?(destination_path("spec"))
+          copy_file "ability_spec.rb", "spec/models/ability_spec.rb"
+        else
+          copy_file "ability_test.rb", "test/unit/ability_test.rb"
+        end
       end
     end
   end

lib/generators/cancan/ability/templates/ability_spec.rb

@@ -0,0 +1,16 @@
+require "spec_helper"
+require "cancan/matchers"
+
+describe Ability do
+  describe "as guest" do
+    before(:each) do
+      @ability = Ability.new(nil)
+    end
+
+    it "can only create a user" do
+      # Define what a guest can and cannot do
+      # @ability.should be_able_to(:create, :users)
+      # @ability.should_not be_able_to(:update, :users)
+    end
+  end
+end

lib/generators/cancan/ability/templates/ability_test.rb

@@ -0,0 +1,10 @@
+require "test_helper"
+
+class AbilityTest < ActiveSupport::TestCase
+  def guest_can_only_create_user
+    ability = Ability.new(nil)
+    # Define what a guest can and cannot do
+    # assert ability.can?(:create, :users)
+    # assert ability.cannot?(:update, :users)
+  end
+end