Run specs all green with no warnings with 2.99.0
Update RSpec to 3.0.0
Convert specs to RSpec 3.0.0 syntax with Transpec

This conversion is done by Transpec 2.2.0 with the following command:
    transpec

* 176 conversions
    from: obj.should_receive(:message)
      to: expect(obj).to receive(:message)

* 68 conversions
    from: obj.should
      to: expect(obj).to

* 47 conversions
    from: obj.stub(:message)
      to: allow(obj).to receive(:message)

* 32 conversions
    from: == expected
      to: eq(expected)

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

* 4 conversions
    from: obj.should_not_receive(:message)
      to: expect(obj).not_to receive(:message)

* 3 conversions
    from: lambda { }.should
      to: expect { }.to

* 1 conversion
    from: Klass.any_instance.should_receive(:message)
      to: expect_any_instance_of(Klass).to receive(:message)

* 1 conversion
    from: lambda { }.should_not
      to: expect { }.not_to

See also: https://github.com/yujinakayama/transpec#supported-conversions