Upgrade rspec to 3.1.0
Convert specs to RSpec 3.1.7 syntax with Transpec

This conversion is done by Transpec 2.3.8 with the following command:
    transpec

* 5 conversions
    from: obj.stub(:message => value)
      to: allow(obj).to receive_messages(:message => value)

For more details: https://github.com/yujinakayama/transpec#supported-conversions