ControllerExampleGroup uses controller as the implicit subject by def…

…ault

Restores functionality from RSpec 1.X.  Hat tip to jferris for the original
patch. (Closes rspec#223)

lib/rspec/rails/example/controller_example_group.rb

@@ -169,6 +169,7 @@ module InstanceMethods
         @routes = ::Rails.application.routes
         ActionController::Base.allow_forgery_protection = false
       end
+      subject { controller }
     end
 
     RSpec.configure &include_self_when_dir_matches('spec','controllers')

spec/rspec/rails/example/controller_example_group_spec.rb

@@ -18,5 +18,32 @@ module RSpec::Rails
       end
       group.metadata[:type].should eq(:controller)
     end
+
+    it "should use the controller as the implicit subject" do
+      group = RSpec::Core::ExampleGroup.describe do
+        include ControllerExampleGroup
+      end
+
+      example = group.new
+
+      controller = double('controller')
+      example.stub(:controller => controller)
+
+      example.subject.should == controller
+    end
+
+    describe "with a specified subject" do
+      before do
+        @group = RSpec::Core::ExampleGroup.describe do
+          include ControllerExampleGroup
+          subject { 'specified' }
+        end
+      end
+
+      it "should use the specified subject instead of the controller" do
+        example = @group.new
+        example.subject.should == 'specified'
+      end
+    end
   end
 end