class RSpec::Mocks::AnyInstance::Recorder

def should_receive(method_name, &block)

Other tags:
    See: Methods#should_receive - 
def should_receive(method_name, &block)
  @expectation_set = true
  observe!(method_name)
  message_chains.add(method_name, PositiveExpectationChain.new(self, method_name, &block))
end