call_original_pass_through.rb

lass One
  2   def original arg
  3     2
  4   end
  5 end
  6
  7 describe "one" do
  8   it 'does things' do
  9     one = One.new
 10     one.stub(:original) do |arg|
 11       if arg == 1
 12         @implementation.call arg
 13       else
 14         1
 15       end
 16     end.and_call_original
 17     one.original(1).should == 2
 18   end
 19 end