state_machine callbacks mock helper. More infos : http://stackoverflow.com/a/29774904/2431728

state_machine_helper.rb

class StateMachineHelper

  module MOCK_METHOD
    ALLOW = :allow
    EXPECT = :expect
  end

  module CALLBACK_TYPE
    BEFORE  = :before
    AFTER   = :after
    AROUND  = :around
    FAILURE = :failure
  end

  # TODO : You need to change the default value of "state_machine_class" parameter if you want one
  #        or just delete the default value if you don't want one
  #
  # Usage : In your Rspec spec, for example :
  #
  #   * StateMachineHelper.new(self).mock_all_callbacks(:toto)
  #
  # where ":toto" is the name of your state machine
  #
  def initialize(rspec_context, state_machine_class = MyClassThatContainsTheStateMachine)
    @rspec_context = rspec_context
    @state_machine_class = state_machine_class
  end

  def allow_all_callbacks(state_machine_name)
    mock_callbacks(state_machine_name, MOCK_METHOD::ALLOW)
  end

  def allow_before_callbacks(state_machine_name)
    mock_before_callbacks(state_machine_name, MOCK_METHOD::ALLOW)
  end

  def allow_after_callbacks(state_machine_name)
    mock_after_callbacks(state_machine_name, MOCK_METHOD::ALLOW)
  end

  def allow_around_callbacks(state_machine_name)
    mock_around_callbacks(state_machine_name, MOCK_METHOD::ALLOW)
  end

  def allow_failure_callbacks(state_machine_name)
    mock_failure_callbacks(state_machine_name, MOCK_METHOD::ALLOW)
  end

  def expect_all_callbacks(state_machine_name)
    mock_callbacks(state_machine_name, MOCK_METHOD::EXPECT)
  end

  def expect_before_callbacks(state_machine_name)
    mock_before_callbacks(state_machine_name, MOCK_METHOD::EXPECT)
  end

  def expect_after_callbacks(state_machine_name)
    mock_after_callbacks(state_machine_name, MOCK_METHOD::EXPECT)
  end

  def expect_around_callbacks(state_machine_name)
    mock_around_callbacks(state_machine_name, MOCK_METHOD::EXPECT)
  end

  def expect_failure_callbacks(state_machine_name)
    mock_failure_callbacks(state_machine_name, MOCK_METHOD::EXPECT)
  end

  private

    # An explanation on how it works : http://stackoverflow.com/a/29774904/2431728
    def mock_callbacks(
      state_machine_name,
      method,
      callback_types = [CALLBACK_TYPE::BEFORE, CALLBACK_TYPE::AFTER, CALLBACK_TYPE::AROUND, CALLBACK_TYPE::FAILURE]
    )
      @state_machine_class
        .state_machines[state_machine_name]
        .callbacks
        .flat_map{ |k, callbackArray| callbackArray if callback_types.include?(k)  }
        .compact
        .find_all{ |callback|
          callback.instance_variable_get('@methods').any? { |callback_method_proc|
            /#{state_machine_class_file_name}/.match callback_method_proc.to_s
          }
        }.map{ |our_callback|
          @rspec_context.send(method, our_callback.branch).to @rspec_context.receive(:if_condition).and_return(lambda {false})
        }
    end

    def mock_all_callbacks(state_machine_name, method)
      mock_callbacks(state_machine_name, method)
    end

    def mock_before_callbacks(state_machine_name, method)
      mock_callbacks(state_machine_name, method, [CALLBACK_TYPE::BEFORE])
    end

    def mock_after_callbacks(state_machine_name, method)
      mock_callbacks(state_machine_name, method, [CALLBACK_TYPE::AFTER])
    end

    def mock_around_callbacks(state_machine_name, method)
      mock_callbacks(state_machine_name, method, [CALLBACK_TYPE::AROUND])
    end

    def mock_failure_callbacks(state_machine_name, method)
      mock_callbacks(state_machine_name, method, [CALLBACK_TYPE::FAILURE])
    end

    def state_machine_class_file_name
      @state_machine_class.name.underscore
    end

end