class ActiveSupport::Testing::SimpleStubs

def unstub_object(stub)

Restores the original object.method described by the Stub 
def unstub_object(stub)
  singleton_class = stub.object.singleton_class
  singleton_class.silence_redefinition_of_method stub.method_name
  singleton_class.alias_method stub.method_name, stub.original_method
  singleton_class.undef_method stub.original_method
end