Mock a Active Record abstract class and how to stub a nil object in rails test::unit/mocha?

Question

i have two question

1.How do i stub a nil object in rails test cases.

2.Mock an Active Record Abstract class

1. I have a application X with a test database X_test, Now i need to stub an database y_test which doesn't exist and which implements Active Record object and is a abstract class

for example

Y::table.find_by_email("hello@gmail.com").selected_lan["iden"]

      module Y
        class table <Base
          belongs_to:selected_lan, :class =>lan
          def self.find_by_email(iden)
           find_by_email(license_iden)
          end
        end
     end

    module Y
       class Base <ActiveRecord::Base
         self.abstract_class = true
       end
    end

Answer 1

Y::table.expects(:find_by_email).with('some@email.com').returns(nil)