gistfile1.rb

describe PeopleController do

 shared_examples 'successful response' do
   it 'should be successful' do
     response.should be_success
   end

   it 'should respond in JSON format' do
     response.content_type.should == 'application/json'
   end
 end

 [...]

 describe 'GET /people/:id (#show)' do
   before :each do
     get :show, :id => Person.first, :format => :json
   end

   it_should_behave_like 'successful response'

   it 'should have your custom behaviour...' do
     # foo
   end
 end

end