How to stub user.trebuchet to always return true for any feature

user_dot_trebuchet_spec.rb

# as a one-liner to use in an rspec example
@user.stub(:trebuchet).and_return(double(@user.trebuchet, :launch? => true))

# more verbose example
it "should stub user.trebuchet"  do
  @user = Factory(:user)
  @user.trebuchet.launch?("something ridiculous").should be_false

  enthusiastic_trebuchet = double(@user.trebuchet, :launch? => true)
  @user.stub(:trebuchet).and_return(enthusiastic_trebuchet)
  @user.trebuchet.launch?("something ridiculous").should be_true
end