interface

Implementable interfaces in ruby

Installation

gem install shuber-interface

require 'interface'

Usage

Simply create a module with any methods that you’d like its implementing objects to define

module RemoteControl
  # turns the device on
  def on
  end

  # turns the device off
  def off
  end
end

Then use the implements method in your classes (also aliased as implement to conform with include and extend naming conventions)

class BrokenDevice
  implements RemoteControl
end

BrokenDevice.new.on # NotImplementedError: BrokenDevice needs to implement 'on' for interface RemoteControl

class WorkingDevice < BrokenDevice
  def on
    @power = true
  end

  def method_missing(method, *args)
    method == :off ? @power = false : super
  end

  def respond_to_missing?(method, include_private)
    method == :off
  end
end

WorkingDevice.new.on # true
WorkingDevice.new.off # false

WorkingDevice.interfaces # [RemoteControl]

Testing interface implementations

Include Interface::TestHelper in your test framework

Test::Unit::TestCase.send(:include, Interface::TestHelper)

Then you can use assert_implements_interfaces (aliased as assert_implements_interface) in your tests

class BrokenDeviceTest < Test::Unit::TestCase
  def test_should_implement_interfaces
    assert_implements_interfaces BrokenDevice.new # Failure: unimplemented interface methods for BrokenDevice: {Remote=>["off", "on"]}
  end
end

You can also explicitly list interfaces to test

module MockInterface end

class BrokenDevice
  implements Remote, MockInterface
end

class BrokenDeviceTest < Test::Unit::TestCase
  def test_should_implement_mock_interface
    assert_implements_interface BrokenDevice.new, MockInterface # passes
  end
end

Note on Patches/Pull Requests

• Fork the project.

• Make your feature addition or bug fix.

• Add tests for it. This is important so I don’t break it in a future version unintentionally.

• Commit, do not mess with Rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)

• Send me a pull request. Bonus points for topic branches.